PROBLEM TO BE SOLVED: To provide a transmission mechanism increased in a gear ratio range and reduced in size. SOLUTION: The control device of a continuously variable transmission is equipped with: first and second pulleys receiving rotation from an engine and supported by first and second pulley shafts, respectively; a belt stretched between the first and second pulleys; a speed change mechanism for performing continuous speed change; a gear ratio setting processing means for setting a gear ratio according to a shift condition; a running state discrimination processing means for discriminating the running state of the vehicle; and an interference avoidance control processing means for performing interference avoidance control that avoids interferences of the belt with one of the first and second pulley shafts in a predetermined running state. In a predetermined running state, the interference avoidance control for avoiding interferences of the belt with the pulley shafts is performed so that the minimum value of an effective diameter of the first and second pulleys is increased. COPYRIGHT: (C)2009,JPO&INPIT