1. An imaging device having a lens means with a single focal point on an imaging surface, wherein the imaging device is configured to have a solid-state imaging element on which a plurality of pixels are arranged in a matrix pattern in the imaging surface, have a light shielding layer provided with a single aperture section and a plurality of light receiving regions for separating and receiving diagonal lights that have passed the aperture section in respectively different directions on the pixels, separate a light from a subject which has entered the imaging surface into a plurality of lights with different directivity, and photoelectrically convert the light for each of the pixels, and simultaneously image the light as a plurality of images.