PURPOSE: To provide a sterilizing tank for medical supplies capable of preventing a sterilization failure and extremely efficiently and effectively sterilizing a material to be sterilized in formaldehyde gas sterilization using, as gas supplying source, a granular powder of plaster of Paris impregnated with formalin.

CONSTITUTION: In a sterilizing tank for medical supplies, a gas generating source of a granular powder 14 of plaster of Paris impregnated with formalin is replaceably arranged in a transparent box 12 surrounded in four sides and having a door 20 for opening and closing a part, and a heater 2, a temperature sensor 3, and an internal circulating blower 1 are similarly installed in the transparent box 12. A temperature regulator 11 having the detection input of the temperature sensor 3 is connected to the heater 2, and the transparent box 12 is kept at a specific temperature by the control of the temperature regulator 11.