A battery voltage control device includes a step-up module that steps up a voltage of a battery and applies the voltage to a driving motor, an image analysis processing module that acquires and analyzes a piece of image information of an outside of a vehicle that is obtained through imaging, and driving state forecast module that forecasts a driving state including starting or stopping of the vehicle based on a piece of environment information of the outside of the vehicle that is obtained through analysis of the piece of image information and controls step-up by the step-up module based on the forecast driving state.