An image forming apparatus capable of switching power state between a first power state and a second power state, which is lower in power than the first power state, shifts from the second power state to the first power state. In a case where the image forming apparatus shifts to the second power state in response to a current time reaching a set time, the image forming apparatus is controlled not to shift from the second power state to the first power state in response to an object approaching the image forming apparatus being detected.