A spectrometer comprising: a light detection element having a substrate made of a semiconductor material, a light passing part provided in the substrate, and a light detection part put in the substrate; a support having a base wall part opposing the light detection element through a space between the light passing part and the light detection part, and side wall parts (32, 33) integrally formed with the base wall part, the light detection element being fixed to the side wall parts, the support being provided with a wiring electrically connected to the light detection part; and a dispersive part provided on a first surface of the base wall part on a side of the space and configured to disperse and reflect light passing through the light passing part to the light detection part in the space, wherein a first end part of the wiring on a side of the light detection part is positioned on an end surface of side wall part and is connected to a terminal provided in the light detection element, and a second end part of the wiring on an opposite side from the side of the light detection part is positioned on a second surface of the base wall part on an opposite side from the side of the space, wherein, by the light detection element being fixed to the side wall parts (32, 33) so as to oppose the first surface of the base wall part, the space with an optical path from the light passing part to the light detection part and the electrical connection of the wiring to the light detection part is provided, the light detection part includes a plurality of photodiodes formed in a first conductivity type region inside the substrate and a second conductivity type region provided within the first conductivity type region, and wherein the substrate is fixed to the support. a light detection element having a substrate made of a semiconductor material, a light passing part provided in the substrate, and a light detection part put in the substrate; a support having a base wall part opposing the light detection element through a space between the light passing part and the light detection part, and side wall parts (32, 33) integrally formed with the base wall part, the light detection element being fixed to the side wall parts, the support being provided with a wiring electrically connected to the light detection part; and a dispersive part provided on a first surface of the base wall part on a side of the space and configured to disperse and reflect light passing through the light passing part to the light detection part in the space, wherein a first end part of the wiring on a side of the light detection part is positioned on an end surface of side wall part and is connected to a terminal provided in the light detection element, and a second end part of the wiring on an opposite side from the side of the light detection part is positioned on a second surface of the base wall part on an opposite side from the side of the space, wherein, by the light detection element being fixed to the side wall parts (32, 33) so as to oppose the first surface of the base wall part, the space with an optical path from the light passing part to the light detection part and the electrical connection of the wiring to the light detection part is provided, the light detection part includes a plurality of photodiodes formed in a first conductivity type region inside the substrate and a second conductivity type region provided within the first conductivity type region, and wherein the substrate is fixed to the support.