A protector for a three-phase electric motor has a container with a housing and a metal plate secured thereto. A protrusion is provided in the housing. Three conductive terminal pins, each with a fixed contact, protrude into the housing through the metal plate. A thermally responsive plate is connected to the three moveable contacts. The thermally responsive plate is dish shaped and reverses its direction of curvature at a predetermined temperature. Three moveable contacts are secured to the thermally responsive plate. An elastic member extends between the protrusion and the thermally responsive plate. A rotation member prevents the thermally responsive plate from rotating, thereby maintaining the moveable contacts in opposition to the fixed contacts. The conductive terminal pins are located at a neutral point side of phase windings of a three-phase motor so that AC current flowing into the three-phase motor is interrupted.