A spectroscope (1A, 1B, 1C, 1D) comprising: 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; and a spectroscopic module (3A, 3B, 3D) supported on the support part within the package; wherein the spectroscopic module (3A, 3B, 3D) has: a light detection unit (20, 60) provided with a light transmission part (22, 63) for transmitting therethrough light incident thereon from the light entrance part; and a spectroscopic unit (30, 70), secured to the light detection unit (20, 60) so as to be arranged on the support part side of the light detection unit (20, 60), including a spectroscopic part (35, 72) for spectrally resolving the light transmitted through the light transmission part (22, 63) while reflecting the light to a light detection part of the light detection unit (20, 60); wherein the lead pins are electrically connected to the light detection part, characterized in that the light detection unit (20, 60) and the spectroscopic unit (30, 70) are secured to each other by spacers arranged between the light detection unit and the spectroscopic unit, the lead pins are fitted into fitting parts (29, 41, 65) provided with the light detection unit (20, 60) and are fitted into fitting parts provided with the spectroscopic unit (30, 70), and the spacers are arranged between the fitting portions of the spectroscopic unit (30, 70) and their vertically opposing fitting portions of the light detection unit (20, 60) so that, through the plurality of lead pins, the light transmission part (22, 63) provided with the light detection unit (20, 60) is positioned with respect to the spectroscopic unit (30, 70) and the light entrance part provided with the package at least in a direction perpendicular to the direction in which the light entrance part and the support part oppose each other. 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; and a spectroscopic module (3A, 3B, 3D) supported on the support part within the package; wherein the spectroscopic module (3A, 3B, 3D) has: a light detection unit (20, 60) provided with a light transmission part (22, 63) for transmitting therethrough light incident thereon from the light entrance part; and a spectroscopic unit (30, 70), secured to the light detection unit (20, 60) so as to be arranged on the support part side of the light detection unit (20, 60), including a spectroscopic part (35, 72) for spectrally resolving the light transmitted through the light transmission part (22, 63) while reflecting the light to a light detection part of the light detection unit (20, 60); a light detection unit (20, 60) provided with a light transmission part (22, 63) for transmitting therethrough light incident thereon from the light entrance part; and a spectroscopic unit (30, 70), secured to the light detection unit (20, 60) so as to be arranged on the support part side of the light detection unit (20, 60), including a spectroscopic part (35, 72) for spectrally resolving the light transmitted through the light transmission part (22, 63) while reflecting the light to a light detection part of the light detection unit (20, 60); wherein the lead pins are electrically connected to the light detection part, characterized in that the light detection unit (20, 60) and the spectroscopic unit (30, 70) are secured to each other by spacers arranged between the light detection unit and the spectroscopic unit, the lead pins are fitted into fitting parts (29, 41, 65) provided with the light detection unit (20, 60) and are fitted into fitting parts provided with the spectroscopic unit (30, 70), and the spacers are arranged between the fitting portions of the spectroscopic unit (30, 70) and their vertically opposing fitting portions of the light detection unit (20, 60) so that, through the plurality of lead pins, the light transmission part (22, 63) provided with the light detection unit (20, 60) is positioned with respect to the spectroscopic unit (30, 70) and the light entrance part provided with the package at least in a direction perpendicular to the direction in which the light entrance part and the support part oppose each other.