The endoscope includes an imaging device 20 at a distal end portion of an insertion portion that can be inserted into a body cavity. The imaging apparatus includes a lens barrel 22 that holds a photographic lens 23, an image sensor 21 that has a rectangular outer periphery shape for photoelectrically converting photographic light incident on the image receiving surface via the photographic lens, and an image receiving surface that is an insertion portion. And a sensor holder 40 for holding the image sensor in a state intersecting with the longitudinal direction. The sensor holder has three independent wall portions 42 that respectively cover the three side surfaces of the image sensor, and is on a plane between adjacent wall portions of the three wall portions on the XY plane orthogonal to the longitudinal direction of the insertion portion. The gap length in the X-axis direction is equal to the gap length in the Y-axis direction between adjacent wall portions. Moreover, the height of each of the three wall portions 42 is 1.5 to 3 times the gap length.内視鏡は、体腔内に挿入可能な挿入部の先端部に撮像装置２０を備える。撮像装置は、撮影レンズ２３を保持する鏡筒２２と、撮影レンズを介して受像面に入射された撮影光を光電変換する受像面の外周形状が矩形のイメージセンサ２１と、受像面が挿入部の長手方向に交差した状態においてイメージセンサを保持するセンサホルダ４０とを備える。センサホルダは、イメージセンサの３つの側面をそれぞれ覆う３つの独立した壁部４２を有し、挿入部の長手方向と直交するＸＹ平面上における、３つの壁部の隣接する壁部間の平面上におけるＸ軸方向の隙間長さと、隣接する壁部間のＹ軸方向の隙間長さとは等しい。また、３つの壁部４２のそれぞれの高さは、上記隙間長さの１．５倍～３倍である。
