According to this invention, in order to provide an image pickup unit with an objective lens unit using a plastic lens which contributes to an improvement in assemblability and has easily achieved a reduction in optical variations by taking member properties into consideration and an endoscope using the image pickup unit, the image pickup unit is configured to include an objective lens unit composed of a plurality of optical members arranged in series with each other in a direction parallel to a single optical axis such that optical axes of the plurality of optical members coincide with each other and a series-connecting portion which unitizes the plurality of optical members and a photoelectric conversion image pickup device which receives an optical image formed by the objective lens unit and performs photoelectric conversion processing, and the series-connecting portion is configured to include a holding portion which holds one of the plurality of optical members, an extending portion which is provided to extend from one end of the holding portion in a direction parallel to the optical axis of the optical member held by the holding portion and is formed to be elastically deformable in a direction almost orthogonal to the optical axis, and an engaging portion which is provided at the extending portion and engages with, of the plurality of optical members, one different from the optical member held by the holding portion.
