A socket housing formed on the side of a solenoid valve body includes a socket thereinside connected with a coil of a solenoid operation section. A power feeding terminal box for holding a pin-shaped power feeding terminal connected with a power feeding line is housed in a terminal cover. Installation of the terminal cover on the side of the solenoid valve body causes the power feeding terminal to be electrically connected with the socket and at the same time the power feeding terminal box to be locked into a locking stopper formed inside the terminal cover, thereby allowing the terminal cover to be locked and held in place.