1. A control device for a vehicle, comprising: an automatic transmission comprising a stepwise variable transmission mechanism to switch a plurality of shift stages by changing a combination of engagement and disengagement of a plurality of friction engaging elements, and a continuously variable transmission mechanism coupled to the stepwise variable transmission mechanism in series and to steplessly change a speed ratio; an engine as a driving source; a motor to assist a driving force of the engine; a hydraulic controller to supply a hydraulic pressure to control the engagement and the disengagement of a friction engaging element of the plurality of friction engaging elements; and a control unit to control the automatic transmission to a target speed ratio through changing a shift stage of the stepwise variable transmission mechanism, wherein: the control unit is configured to perform a learning control that learns at least one of a hydraulic pressure of the engagement or the disengagement of the friction engaging element in changing the shift stage of the stepwise variable transmission mechanism, and the control unit is configured to inhibit an assist of the driving force to the engine by the motor in performing the learning control.