Provided is an endoscope achieving reduction in diameter of an insertion section, and achieving high quality image. An endoscope includes an imaging unit disposed at a distal end portion of an insertion section inserted into a body of a subject, and a built-in component provided parallel with the imaging unit at the distal end portion, and extending substantially parallel with an axial direction of the insertion section. The imaging unit has a solid state image sensor having a light receiving unit, and a rigid circuit board at least partially disposed on a proximal end side of the endoscope relative to the solid state image sensor, and electrically connected to the solid state image sensor. The rigid circuit board has a first surface having a longitudinal direction extending in an axial direction of the distal end portion； and a second surface opposed to the first surface substantially in parallel, the first surface has a width larger than a width of the second surface in a cross-section orthogonal to the longitudinal direction. The rigid circuit board has a third surface and a fourth surface different from the first surface and the second surface, and extending in the axial direction of the distal end portion, and the third surface or the fourth surface is opposed to the built-in component.
