Patent ID: 8110802

Claim:
A photodetecting device comprising: a photodetecting element that detects light made incident from a back surface of the photodetecting element by a photodetecting section being on a front surface side of the photodetecting element; a wiring board provided at the front surface side of the photodetecting element and electrically connected with the photodetecting section; and a base provided at an opposite side of a photodetecting element side of the wiring board and to be installed on a predetermined installation body, wherein a positional alignment mark to serve as a positional reference of the photodetecting element is formed on the front surface of the photodetecting element, a window portion to expose the positional alignment mark is formed on the wiring board, and the base has a positioning portion positioned with respect to the positional alignment mark exposed from the window portion, and a fitting portion positioned with respect to the positioning portion and to be fitted with the installation body, wherein the wiring board and the base are formed separately.