This invention relates to a machine tool having two main spindles which are subject to driving control by servomotors (1 and 2) by giving velocity commands (Vcmd1) and (Vcmd2) for controlling, respectively, the speed of rotation of a first main spindle and that of a second main spindle to speed control circuits (3 and 4), thereby controlling the two main spindles of a machine tool such as a lathe in synchronous operation in order to machine a work efficiently. In the present invention, the angles of rotation of the main spindles are brought into conformity to effect the synchronous operation without fail and to enable a catch of another work during rotation.