A numerical controller that shortens time required for transferring control of a spindle between control systems. When the spindle control command is included, the command is carried out and information on designation of the spindle, commanded rotational velocity and direction is stored in a case of a velocity control mode, and information on designation of the spindle, commanded rotational position and velocity is stored in a case of a position control mode. When a command to cancel the control of spindle is read, the control of the designated spindle and also the stored information on the control status of the spindle are transferred to the other control system. A command to acquire the control of the spindle is read in a machining program for the other control system, the control of the designated spindle is started by the other control system according to the transferred control status of the spindle.