The object of the invention is to provide a light receiving amplification element
applicable to an optical pickup apparatus comprising a semiconductor two-wavelength
laser element and one condensing lens. The light receiving amplification element
is provided with a plurality of light receiving portions corresponding to different
wavelengths, a plurality of trans-impedance type amplifiers connected to the light
receiving portions according to the different wavelengths and adaptable to the
different wavelengths and switching portion for switching output from the trans-impedance
type amplifier according to each of the wavelengths.