An imaging device includes two imaging optical systems each of the imaging optical systems including a wide-angle lens having an angle of view wider than 180 degrees, and an imaging sensor configured to image an image by the wide-angle lens, so as to obtain an image in a solid angle of 4π radian by synthesizing the images by the respective imaging optical systems, wherein the wide-angle lens of each of the imaging optical systems includes, in order from an object side to an image side, a front group having a negative power, a reflection surface and a back group having a positive power, and is configured to bend an optical axis of the front group by the reflection surface at 90 degrees toward the back group.