A motor includes a motor section and an amplifier section. The motor section and the amplifier section are electrically and mechanically connected with each other via a wire connection base using a screw. A pitch diameter for a plurality of electrical connection parts of the wire connection base with the motor section disposed on a circumference whose center is at a shaft center of the rotating shaft is set to be smaller than a pitch diameter for a plurality of electrical and mechanical connection parts with the amplifier section. The amplifier section includes a plurality of circuit substrates disposed in a layered form in a direction perpendicular to the rotating shaft, and the plurality of circuit substrates are electrically and mechanically screw-fastened to the plurality of electrical and mechanical connection parts of the wire connection base with the amplifier section via a conductive spacer.