An electric toothbrush including: a casing serving as a handle; a linear actuator disposed in the casing; and a replacement brush removably attached to an end portion of the output member of the linear actuator, the end portion projecting from the casing to outside, the linear actuator comprising: an output member supported on a fixing-side member so as to linearly reciprocate freely; an elastic member for biasing the output member to a middle position of the linear reciprocation; a permanent magnet fixed to the output member; a coil for linearly reciprocating the output member by having a variable magnetic field act on the permanent magnet, the coil being fixed to the fixing-side members such that the coil faces one of magnetic poles (14a, 14b) of the permanent magnet; a yoke composed of a ferromagnetic member, the yoke having a midway portion tightly secured to the other magnetic pole of the permanent magnet, extending to the exterior of the coil along the exterior of the permanent magnet with a space from the permanent magnet, having an end portion disposed close to the exterior of the coil; and power supplier means for forming a variable magnetic field on the coil. a casing serving as a handle; a linear actuator disposed in the casing; and a replacement brush removably attached to an end portion of the output member of the linear actuator, the end portion projecting from the casing to outside, the linear actuator comprising: an output member supported on a fixing-side member so as to linearly reciprocate freely; an elastic member for biasing the output member to a middle position of the linear reciprocation; a permanent magnet fixed to the output member; a coil for linearly reciprocating the output member by having a variable magnetic field act on the permanent magnet, the coil being fixed to the fixing-side members such that the coil faces one of magnetic poles (14a, 14b) of the permanent magnet; a yoke composed of a ferromagnetic member, the yoke having a midway portion tightly secured to the other magnetic pole of the permanent magnet, extending to the exterior of the coil along the exterior of the permanent magnet with a space from the permanent magnet, having an end portion disposed close to the exterior of the coil; and power supplier means for forming a variable magnetic field on the coil. an output member supported on a fixing-side member so as to linearly reciprocate freely; an elastic member for biasing the output member to a middle position of the linear reciprocation; a permanent magnet fixed to the output member; a coil for linearly reciprocating the output member by having a variable magnetic field act on the permanent magnet, the coil being fixed to the fixing-side members such that the coil faces one of magnetic poles (14a, 14b) of the permanent magnet; a yoke composed of a ferromagnetic member, the yoke having a midway portion tightly secured to the other magnetic pole of the permanent magnet, extending to the exterior of the coil along the exterior of the permanent magnet with a space from the permanent magnet, having an end portion disposed close to the exterior of the coil; and power supplier means for forming a variable magnetic field on the coil.