An imaging device determines an in-focus position by contrast autofocus. The device includes a first optical system including a first lens and a first image sensor, a second optical system including a second lens and a second image sensor, a signal processing unit to read an image signal from at least one of the first image sensor and the second image sensor and generate an image for display, and a display unit to display the generated image. In the contrast autofocus, the signal processing unit reads a part of the image signal from the first image sensor and calculates a contrast value based on the read part of the image signal, and generates the image for display from the image signal read from the second image sensor.