As a result guarantee contract of, obligation transferred from conscience principal into conscience guarantor. In fact this work is adopted to guarantee by imami jurisprudent. It must be understood, transfer conscience is not nature of guarantee contract of, but it effect of absolute contract, obligation principal may have assurance as mortgage, in jurisprudence all those who have commented on this issue, because the guarantee contract of, is performance obligation, Consequently, with the conclusion of the contract of guarantee, assurance principal obligation is separated. Since assurance is security for performance principal obligation, however in civil law, the majority of lawyers, dependency it for principal obligation, since in guarantee contract of, principal obligation is not dissolved, but transferred into conscience guarantor, the assurance is not separated, unless in hereof be conditioned, of course in guarantee joint and several, since by conclusion of guarantee contract of, is joint conscience, this subject don’t plan, and only add for assurance, with considering importance this subject, will study in Iran and French law, finally selected comment will be expression.