A waveguide device that guides light through a core part formed in a cladding part is disclosed. The waveguide device includes a waveguide part formed in the cladding part so as to have the same refractive index as the refractive index of the core part so that the waveguide part communicates with the core part, and a reflective part configured to perform at least one of reflecting the light guided by the core part toward the waveguide part and reflecting light from the waveguide part toward a direction in which the light is guided by the core part.