An imaging unit includes an image pickup element extending along a surface parallel to an imaging surface, a circuit board including a circuit to drive the image pickup element, and a plurality of fixing members to fix the image pickup element and the circuit board. The circuit board includes at least one through hole on a straight line that extends in a longitudinal direction of the image pickup element and is provided with the plurality of the fixing members. The through hole is provided at a position between at least two of the plurality of the fixing members on the straight line.