The invention provides an optical device which can easily ensure the structure of a maintaining force of an optical member, an electronic endoscope and a manufacturing method of the optical device. The optical device of the electronic endoscope is provided with a prism (41), a prism holder (40) for holding the prism (41) on an end surface (54) side with an opening (51), and a parallel planar board (52) held in the opening (51) of the prism holder (40). A space (55) is formed between a plane on the end surface (54) side of the parallel planar board (52) held in the opening (51) and an abutting surface (41a) of the prism (41) abutted against the end surface (54) of the prism holder (40). A binder layer including a binder for binding the prism (41) with the parallel planar board (52) is arranged in the space (55).
