Even when a power switch is turned off, the controller of an injection molding machine does not shut off a power supply immediately. The controller determines whether the present state of the injection molding machine is a previously-set confirmation-requiring state, such as a lockup state of a mold clamping unit using a toggle link mechanism, or a nozzle touch state of an injection unit. When the present state is not the confirmation-requiring state, the controller shuts off the power supply. When the present state is the confirmation-requiring state, the controller displays on a display screen a confirmation window for confirmation of power shut off. The controller shuts off the power supply in accordance with a shut-off operation performed on the basis of the confirmation window.