Provided is an endoscope apparatus that can improve the airtightness of a space within a connector part where an optical semiconductor element or the like is present. The endoscope apparatus includes a connector part that is connected to an external device and transmits and receives light signals to and from the external device. The connector part includes a hollow metal member having two openings that communicate with each other, a light emitting element that is press-fitted and fixed to one opening side of the hollow metal member so as to be capable of sealing the periphery of the one opening, a lens that is provided on the other opening side of the hollow metal member, a fixing member that fixes the lens to the hollow metal member, and an O ring that is pressed by the fixing member and seals a gap between the lens and the hollow metal member.
