Abstract: An electromagnetic valve comprises a valve housing including a inlet port and a exhaust port a motor housing disposed therein an electromagnetic mechanism including a solenoid coil, a yoke magnet, a fixed core and a movable core a valve member linearly movable disposed so as to open-close the communication between the inlet port and the outlet port with the movement of the movable core a diaphragm member having an outer periphery secured to between the both housings and an inner periphery secured to the movable core, and defines a back pressure chamber and pressure chambers communicated with the both ports, respectively, in said valve housing. The diaphragm member having an effective sealing area which is substantially equal to an effective sealing area of the valve member. The movable core is provided with a passage means which communicates between the inlet port and the back pressure chamber when the valve member is closed position.