Stereo image pickup unit

A stereo image pickup unit comprising:

• a pair of objective optical systems disposed having a parallax;
• a pair of image pickup apparatuses each including an image pickup device and a substrate connected to rear surface of the image pickup device;
• and
• a holding member configured to hold the pair of image pickup apparatuses such that optical images respectively formed by the pair of objective optical systems are guided to the image pickup devices of the pair of image pickup apparatuses, wherein
• the pair of image pickup apparatuses is formed in a same shape each other,
• the substrate included in each of the pair of image pickup apparatuses includes a plurality of surface sections perpendicular to the rear surface of the image pickup device,
• the plurality of surface sections include surface sections projecting from a direction of one side of the image pickup device toward an outer side of a projection surface of the image pickup device and formed by unmounting surfaces on which a component is not mounted,
• the holding member holds the pair of image pickup apparatuses such that the surface sections projecting toward the outer side of the projection surface are opposed to one another on a parallax direction inner side, and
• the substrate is a laminated substrate in which a plurality of circuit boards are laminated in the parallax direction.