To suppress a shortage in light quantity during photographing, in an image pickup device capable of simultaneously performing phase difference AF and live view.

The image pickup device 1 includes a half mirror 6 for separating light from a photographing optical system into transmitted light and reflected light, a phase difference system AF sensor 7 for receiving the reflected light reflected by the half mirror 6 and detecting a focusing state by the phase difference system, an imaging element 5 for receiving the transmitted light transmitting through the half mirror 6 and generating an image of time series related to a subject image, and displaying means 8 and 12 for displaying the image of time series generated by the imaging element 5. The half mirror 6 is disposed movably between a first position PG 1 existing on a light path of the subject image from the photographing optical system, and a second position evacuated from the light path of the subject image. When the half mirror 6 exists at the second position, the imaging element 5 generates an image for photographing based on the subject image reaching the imaging element 5 from the photographing optical system without transmitting through the half mirror 6.