1. A control device for an infinitely variable transmission for a vehicle, the infinitely variable transmission comprising an input shaft, a continuously variable transmission which outputs the rotation of the input shaft at an arbitrary speed ratio, a fixed speed ratio transmission which outputs the rotation of the input shaft at a fixed speed ratio, and an output shaft which changes a rotation direction and a rotation speed according to a difference between an output rotation speed of the continuously variable transmission and an output rotation speed of the fixed speed ratio transmission, the device comprising: a sensor which detects a running state of the vehicle; a sensor which detects a real vehicle acceleration; and a programmable controller programmed to: calculate a target speed ratio of the continuously variable transmission based on the running state of the vehicle; set a target vehicle acceleration based on the running state of the vehicle; calculate an acceleration deviation of the target vehicle acceleration from the real vehicle acceleration; determine if a predetermined creep torque control condition holds based on the running state of the vehicle; calculate a corrected target speed ratio, if the predetermined condition holds, to cause the acceleration deviation to decrease; and control the speed ratio of the continuously variable transmission based on the corrected target speed ratio.