PURPOSE: To control not only steam pressure but also a temperature so as to supply desired steam by inputting set pressure and a set temperature from a setting input means without using a pressure sensor and a temperature sensor.

CONSTITUTION: When the set temperature is inputted from a set temperature input means 7, a storage part calculates steam pressure to a set temperature value and the elastic force of a coil spring 15. A motor 17 is rotated and the coil spring 15 is compressed. Then, steam supplied from a steam supply pipe 2 is restricted by a main valve 8 and distilled liquid in a steam pot is heated. Set pressure is inputted from a set pressure input means 6, the elastic force of the coil spring 15 to the set pressure of the storage part is calculated, the elasticity of the coil spring 15 is adjusted and the steam of desired pressure is supplied from a control valve 1 to the steam pot. When pressure drops, a diaphragm 12 is pushed down, a pilot valve 11 is opened, the main valve 8 is opened and the secondary-side of the control valve 1 is maintained to a set pressure value.