To provide an imaging apparatus capable of suitably detecting the focus of an optical system.

An imaging apparatus includes: an imaging part 22 that photographs images by photographic optical systems 31, 32, and 33 to output picture signals corresponding to photographed images; a mechanical shutter 23; an electronic shutter; a receiver for focus detection having a plurality of pixels for focus detection that generates a pair of image signals formed by a pair of light fluxes passing through the photographic optical systems 31, 32, and 33; an addition part that adds image signals generated by the plurality of pixels for focus detection; a focus detection part that detects focus states of the photographic optical systems 31, 32, and 33 based on the added image signals; and a control part that switches a shutter for photographing between the mechanical shutter 23 and electronic shutter. The addition part sets smaller number of addition of image signals when performing continuous photographing by the imaging part 22 using the mechanical shutter 23 than when using the electronic shutter.