A spectroscope comprises a package provided with a light entrance part, a plurality of lead pins penetrating through a support part opposing the light entrance part in the package, a light detection unit supported on the support part within the package, and a spectroscopic unit supported on the support part within the package so as to be arranged on the support part side of the light detection unit. The light detection unit has a light transmission part for transmitting therethrough light incident thereon from the light entrance part. The spectroscopic unit has a spectroscopic part for spectrally resolving the light transmitted through the light transmission part while reflecting the light to a light detection part. The lead pins are fitted into fitting parts provided with the light detection unit and electrically connected to the light detection part.