Spectrometer module

A spectroscopic module comprising:

• a main unit provided with a depressed portion having a concave curved surface and opening to one side;
• a first reflection layer, formed on the curved surface, for reflecting light incident on the depressed portion to the one side of the main unit;
• a second reflection layer for reflecting the light reflected by the first reflection layer;
• a third reflection layer, formed on the curved surface, for reflecting the light reflected by the second reflection layer to the one side of the main unit;
• a photodetector, supported so as to oppose the curved surface, for detecting the light reflected by the third reflection layer;
• and
• a light entrance portion for letting the light into the depressed portion,
• wherein at least the third reflection layer disperses the light reflected by the second reflection layer,
• wherein the second reflection layer is located between a light detecting portion of the photodetector and the light entrance portion when seen from the one side of the main unit, and
• wherein the second reflection layer and the light detecting portion of the photodetector are provided along a plane perpendicular to an incident direction of light entering into the light entrance portion.