directly without using the rotary table the shaft 2 a of the rotary table is rotatably supported in a casing 1 a via a housing 1 b using a main bearing 3 a and a support bearing 3 b the shaft 2 a has such a configuration that a plurality of components are connected by volts or the like a stator 4 b of a motor a cylinder 7 b of a brake a sensor head 5 b and a lid 8 are secured to a casing 1 a and a rotor 4 a a sensor gear a position detector 5 a and a brake disc 6 are secured to the shaft 2 a using volts or the like so as to be integrally rotatable with a rotary table not shown in the figure thus the rotor 4 a and the stator 4 b compose a motor rotated with a rotary table not shown in the figure driven directly as the shaft 2 a rotates the sensor gear 5 a rotates a sensor head 5 b detects the rotation of the sensor gear 5 a and outputs a pulse signal which corresponds to the rotation amount to a controller of a machine tool not shown in the figures or the like a piston 7 a with forward and backward stroke in a cylinder 7 b is.