The invention relates to a controller for a vehicle having installed thereon a drive power source, a transmission, and a torque converter that is equipped with a lockup clutch and is provided between the drive power source and the transmission. The controller includes a detection unit that detects an actual revolution speed of the drive power source, and a control unit that controls the lockup clutch so that a state of the lockup clutch becomes any state from among a disengaged state, an engaged state, and a slip state. When executing a slip control, the control unit compares the actual revolution speed with the target revolution speed, and feedback controls a transmission torque of the lockup clutch on the basis of a comparison result of the actual revolution speed and a target revolution speed so as to cause the actual revolution speed to follow the target revolution speed.