To provide an electret having high stability with time and thermal stability of retained electric charge and having excellent charge retention performance, and an electrostatic induction conversion device comprising such an electret. This has been done by providing an electret obtained from a composition comprising a compound (A) having a molecular weight of from 50 to 2000 and having at least two polar functional groups, and a polymer (B) having a number average molecular weight of more than 2000 and having reactive functional groups reactive with the above polar functional groups and an electrostatic induction conversion device comprising such an electret.