An image pickup apparatus includes an optical unit in which a plurality of lenses have relative positions fixed by a transparent resin that fills spaces among the plurality of lenses, and an image pickup substrate in which a light receiving section configured to receive light that is caused to be incident from the optical unit is formed on a principal surface, the optical unit being bonded to the principal surface via an adhesive, and the optical system includes an objective optical system including a plurality of lenses, and inter-lens distances of the plurality of lenses are defined by a spacer, a diaphragm, or the transparent resin.