A miniature d-c motor comprising a case on the inner circumferential surface of which a permanent magnet is mounted, a rotor consisting of an armature and a commutator, and a case cap on which brushes and input terminals are mounted; the rotor being supported via bearings provided on the case and the case cap, in which the miniature d-c motor is housed in a hermetically-sealed internal space defined by the hermetic case formed into a bottomed hollow cylindrical shape and the hermetic case cap fitted to an open end of the hermetic case, and an output shaft connected to a rotor shaft via a magnetic coupling is rotatably provided outside the bottom of the hermetic case.