An imaging unit and an endoscope apparatus capable of decreasing the diameter of a distal end of an insertion unit are to be provided. An imaging unit 40 according to the present invention includes: a solid state image sensor 44 which generates an electrical signal by performing photoelectric conversion on received light； a flexible printed circuit board 45 which includes an inner lead 45f connected to an electrode pad 44a of the solid state image sensor 44 and extends from a side opposite to a light-receiving surface of the solid state image sensor 44； and a multi-layer substrate 46 mounted on a first surface, which is a surface nearer the solid state image sensor 44, of the flexible printed circuit board 45, where the flexible printed circuit board 45 includes an insulating base material 45a, a first surface-side wiring layer 45b formed on a side of the first surface of the base material 45a, and a first surface-side electrical insulating film 45c insulating the first surface-side wiring layer 45b, and the inner lead 45f is formed from the first surface-side wiring layer 45b.
