To obtain a processing agent for silver halide photographic sensitive materials prepd. by using ascorbic acid which is good to environment and has high safety and its deriv. into a main chemical for developing by incorporating a specific compd. into the processing agent and incorporating a redox compd. which releases a development restrainer when oxidized into the agent.

The compd. expressed by formula is incorporated into the processing agent having the silver halide photographic sensitive materials having at least one layer of silver halide emulsion layers on one surface of a base without substantially incorporating hydroquinone into the compd. In addition, the redox compd. which releases the development restrainer when oxidized is incorporated therein. In the formula, R1, R2 respectively independently denote a substd. or unsubstd. (alkyl group, amino group, alkoxy group, alkylthio group); R1 and R2 may form a ring by bonding to each other; (k) denotes 0 or 1; X denotes -CO- or -CS- when k=1; M1, M2 respectively denote hydrogen atoms or alkaline metals.