PURPOSE: To provide a smooth acceleration feeling by a method wherein when a select down shift from an ordinary running range to an engine brake range is detected, a change gear speed of change gear ratio variation control is regulated based on an accelerator opening detecting value.

CONSTITUTION: When a step motor 108 controlled by a change gear control device 300 is operated according to a given gear shift pattern, a change gear ratio is changed following the operation thereof, and a continuously variable gear shift mechanism is shifted and controlled. In the change gear control device, a rotation angle is decided according to a step motor drive signal fed according to a running state. A sensor 303 to detect the throttle opening of an engine as a voltage signal outputs an analogue signal as a throttle opening equivalent to a pedaling amount of an accelerator pedal. A CPU 313 in the change gear control device connected to an address buss 319 and a data buss 320 performs given processing based on data from sensors 301, 302, 305, and 306. Thus, a target drive speed to control a step motor drive amount is set and a change gear ratio is controlled according to computation processing of microcomputer 300.