To provide the optical pickup device capable of facilitating its assembly and adjustment by manufacturing individual optical parts into an integrated type structure.

A silicon substrate 110 is installed parallel to a recording surface of an optical disk 180. A transmissive prism 160 is installed on this silicon substrate. A diffraction grating surface 140 is formed on one side surface of the prism 160. A beam splitter 161 for partial reflection and partial transmission is slantwise installed inside the prism 160. A laser beam projected from a laser light source part 130 is transmitted through the diffraction grating surface 140, and is then reflected by the beam splitter 161. This reflected beam is transmitted through a selective light- transmission part 150 in an upper surface of the prism 160, and is then focused on the optical disk 180 by an objective lens 170. The light beam is totally transmitted through an inner side circular part of the selective light-transmission part 150, and is partially translucentwise transmitted through its surrounding part. A reflected beam from the optical disk 180 is partially transmitted through the beam splitter 161, and is then reflected by a reflecting surface of a bottom surface of the prism 160, and this reflected beam is received by a photodetector on the upper surface of the prism 160.