PURPOSE: To provide a solid treating agent for photograph which is chemically stable and to minimize the volume of the container by wrapping each one solid treating agent in a package to be put in a treating tank or a dissolving tank so that moisture proof can be maintained.

CONSTITUTION: Each solid photographic treating agent 10 is wrapped in a bag (pillow package) 11 or PTP(press-through-pack) package. A photographic material to be developed is carried by a carrier roller 3 from the entrance of an automatic developing device and passed through treating tanks and a drying tank and discharged through the exit. The solid photographic treating agent 10 is directly put in the treating tank 2 for which the agent is required or put in a dissolving tank 6. The treating liquid in the dissolving tank 6 is circulated along the direction of an arrow in the figure by a pump 7 from the treating tank 2 to the dissolving tank 6 so that the solid photographic treating agent 10 put in the dissolving tank 6 is dissolved with lapse of time and circulated into the treating tank 2.