An image pickup apparatus includes a first timer configured to start measuring a first time period when a mirror located at a mirror-up position is moved to a mirror-down position, a second timer configured to start measuring a second time period when the mirror reaches the mirror-down position, and a controller configured to enable processing when the first timer finishes measuring the first period and the second timer finishes measuring the second period. The first period is a time period enough to attenuate mirror's bounds after the mirror located at the mirror-up position starts moving to the mirror-down position, when a high power-supply voltage is set to the image pickup apparatus, and the second period is a time period enough to attenuate mirror's bounds after the mirror reaches the mirror-down position, when a low power-supply voltage is set to the image pickup apparatus.