Opinion of the Court
CRAWFORD, Judge:1. Contrary to his pleas, appellant was convicted of signing a false official record and larceny, in violation of Articles 107 and 121, Uniform Code of Military Justice, 10 USC §§ 907 and 921, respectively. The convening authority approved the sentence of a bad-conduct discharge, 4 months’ confinement, partial forfeitures, and reduction to the lowest enlisted grade. The Court of Military Review1 affirmed the findings and sentence in an unpublished opinion. We granted review on the following issue:2
WHETHER THE MILITARY JUDGE ERRED AS A MATTER OF LAW IN FAILING TO INSTRUCT THE MEMBERS THAT THE DEFENSE OF MISTAKE OF FACT APPLIED TO CHARGE I AND ITS SPECIFICATION, THE FALSE OFFICIAL STATEMENT [SIC].
FACTS
2. On April 30, 1990, appellant signed a “Recertification of Basic Allowance for Quarters (BAQ) — Variable/Rent Plus Housing Allowance (VHA/RPHA)” certifying that he had “provided adequate support for” his “dependents for the last 2 years.”
3. In January 1985, appellant married 15-year-old D J while on a shopping trip with DJ and her parents in Mexico. Since DJ had been a runaway, her parents conceived of the marriage to protect her and them from legal difficulties. DJ’s mother also held out the possibility of appellant’s entitlement to additional money from the Air Force if he were married. CMR unpub. op. at 2. After the marriage, appellant moved in with DJ and her parents for approximately 2 months and provided her with some financial support for about 6 weeks. Thereafter, appellant rented an off-base apartment, but DJ refused to leave her parents’ home. The marriage was never consummated. In August 1985, DJ moved to England with her family when her father was reassigned. This was the last time appellant had contact with her. He provided no further support for her beyond the first 6 weeks of their marriage. From 1985 thru March 1991, appellant received basic allowance for quarters (BAQ) at the “with dependents rate,” along with a variable housing allowance (VHA). CMR unpub. op. at 2.
4. In April 1990, appellant recertified on Air Force Form 987 that he had provided support for DJ as his dependent for the preceding 2 years, thus giving rise to the charge of making a false official statement. He also listed DJ as residing at his current address, even though he did not know where she was and had had no contact with her since 1985. Appellant admitted that he was wrong to take the money, CMR unpub. op. at 2, but that he had been advised by a Finance clerk that he was entitled to the dependent rate for BAQ and VHA until he was divorced. Under these facts, the judge refused to give a mistake-of-fact instruction as to the false official statement.3
DISCUSSION
5. “[A] military judge has a sua sponte duty” to give “appropriate instructions” on affirmative defenses “reasonably raised by the evidence.” United States v. Tatum, 36 MJ 302, 304 ¶ 11 (CMA 1993); see United States v. McMonagle, 38 MJ 53, 58 ¶ 24 (CMA 1993).
6. Criminal conduct involves an act, usually by the accused, mens rea and appropriate notice. RCM 916(j), Manual for Courts-Martial, United States, 1984, provides that an honest (subjective) mistake of fact is a defense to a specific-intent element. A mistake of fact negates the mens rea which is essential to the crime charged. See *444W. La Fave and A. Scott, Substantive Criminal Law § 5.1 at 575 (1986). Thus a mistaken belief will exonerate appellant as to the element requiring specific intent. When there is a specific-intent element, that belief need only be honest to benefit appellant.
7. The elements of signing a false official record are as follows:
(1) That the accused signed a certain official document or made a certain official statement;
(2) That the document or statement was false in certain particulars;
(3) That the accused knew it to be false at the time of signing it or making it; and
(4) That the false document or statement was made with the intent to deceive.
Para. 31b, Part IV, Manual, supra.
8. If a servicemember knowingly signs a false official record, he cannot thereafter complain that he had made an honest mistake as to his intent for, in that .instance, his falsity defeats the honesty of his purpose. Thus, it does not matter if he honestly believed he was entitled to the housing allowance; he cannot, as a matter of law, sign false documents to obtain the allowance.
9. He may, however, have made an honest mistake as to the falsity or officiality of the statements. Such is not the case here. Appellant certified that he provided adequate support to his dependent for the last 2 years. By his own admission he had not provided any support to his wife, let alone “adequate support.” He had no contact with her since August 1985. The statement by the finance clerk did not change that fact. Under these circumstances appellant is not blameless or free from moral culpability. The actions by appellant were not an honest mistake because he knew the correct facts. RCM 916(3).
The decision of the United States Air Force Court of Military Review is affirmed.
Judges COX and GIERKE concur.. See 41 MJ 213, 229 n. * (1994).
. We also granted review of the issue disposed of by United States v. McElroy, 40 MJ 368, 371-72 ¶¶ 13-16 (CMA 1994), cert. denied,-U.S.-, 115 S.Ct. 1256, 131 L.Ed.2d 137 (1995).
. The judge did give the mistake-of-fact instruction on the larceny specification. The court members found appellant guilty of that specification.