To obtain a heat developable photosensitive material having high sensitivity, high Dmax and satisfactory image quality by incorporating a specified hydrazine deriv. as well as an org. silver salt, silver halide and a reducing agent.

A hydrazine deriv. represented by the formula is incorporated into a heat developable photosensitive material contg. an org. silver salt, silver halide and a reducing agent. In the formula, R1 is alkyl, aryl, etc., R2 is an aliphatic group such as 1-30C optionally substd. straight chain, branched or cyclic alkyl or alkenyl, preferably methyl substd. by three aryl groups, G1 is -COCO-, -SO2-, etc., both A1 and A2 are H or one of them is H and the other is optionally substd. alkylsulfonyl, optionally substd. arylsulfonyl, etc., and each of A1 and A2 is preferably H.