An optical displacement detection apparatus includes a scale and a sensor head. A transistor oscillator movement, is used to rotate the display. This image pickup device comprises a semiconductor substrate, provided with the CCD reading part on a front surface that opposes a back surface, which serves as a light-incident surface, a package having a cavity in which the semiconductor substrate is fixed, a cover covering an upper opening of the cavity, an FOP joined to the semiconductor substrate, and electrical wirings.