A thermal protector for a hermetic electrically-driven compressor includes a thermal switch and a cluster socket. The protector is mounted inside a compressor housing on a terminal assembly mounted in a wall of the compressor housing. A casing of the thermal switch and a header plate hermetically closing an open end of the casing integrally form a flange on the peripheral edges when the header plate is secured to the casing. The thermal switch has two terminals one of which is provided with a receptacle into which one of terminal pins of the terminal assembly is fitted, and the other terminal is connected to a common lead wire of a compressor motor. The cluster socket has a plurality of terminal cavities for connecting windings of the motor to the terminal assembly. A body of the socket has a face having a pair of holding portions for holding the flange. Each holding portion has a hook-shaped portion at an end. The casing and the socket are integrally connected together such that a large part of the casing is exposed outside the socket body, when the flange is held by the holding portions and the receptacle is inserted to a position where it is opposed to the one terminal pin of the terminal assembly.