The imaging unit 1 includes an imaging unit 20 in which a plurality of semiconductor elements 22 to 25 including an imaging element 22 are stacked, and a frame member 10 in which the imaging unit 20 passes through the hollow portion H10. The unit 20 has a first side 20S1 orthogonal to the main surface of the image pickup device and a second side 20S2 opposite to the first side 20S1, and four of the first side 20S1 of the imaging unit 20 Of the sides, two sides 20L1 and 20L2 orthogonal to the main surface of the imaging device are in contact with the inner surface of the frame member 10, and the second side surface 20S2 is not in contact with the inner surface of the frame member 10.撮像ユニット１は、撮像素子２２を含む複数の半導体素子２２～２５が積層されている撮像ユニット２０と、撮像ユニット２０が、中空部Ｈ１０を挿通している枠部材１０と、を具備し、撮像ユニット２０は、前記撮像素子の主面と直交する第１の側面２０Ｓ１と第１の側面２０Ｓ１と対向している第２の側面２０Ｓ２とを有し、撮像ユニット２０の第１の側面２０Ｓ１の４辺のうちの前記撮像素子の前記主面と直交する２辺２０Ｌ１、２０Ｌ２は、枠部材１０の内面に当接しており、第２の側面２０Ｓ２は枠部材１０の内面に当接していない。
