A selector valve, comprising a valve chamber having a first valve seat and a second valve seat facing the first valve seat, a first fluid passage communicating with a first valve port on the periphery of the first valve seat of the valve chamber to flow a first working fluid therein, a second fluid passage communicating with the valve chamber to flow the working fluid therefrom or therein, a third fluid passage communicating with a second valve port on the periphery of the second valve seat of the valve chamber to flow the working fluid therefrom, a valve element disposed in the valve chamber and alternately separating from and coming into contact with the first valve seat and the second valve seat, a stem part connected to the valve element, a guide hole movably guiding the valve stem, a storage chamber for a seal means installed around the guide hole, an auxiliary passage allowing the storage chamber to communicate with the first fluid passage, and a solenoid part connected to the stem part for operating a solenoid rod. A first pressure receiving area formed by the first valve seat and the valve element joined to each other to receive the pressure of the first working fluid is set approximately the same as the third pressure receiving area of the stem part receiving the first working fluid in the storage chamber.