PURPOSE: To speed up the signal of amplifier circuit element or operation circuit element as well as to improve the response/sensitivity characteristics of photodiode by allowing the density of low impurities formed in photodiode (PD) area or the thickness of intrinsic layer to be larger than the carrier traveling distance.

CONSTITUTION: A P-type silicon substrate 1 is formed with a recess in the element area of a PD 2 and an N+ buried layer 4 is formed on the bottom surface of the recessed section or wall surface. Furthermore, an N- epitaxial layer 4 is also formed on the section surrounded with the layer 4 and the layer section extending to a P+ layer 6. Therefore, the layer 5 of the PD 2 is formed thick, so that its thickness (a) is made about 5 times larger than the thickness (b) of 2 layers consisting of an N- epitaxial layer 8 and P+ layer 9 on a Tr 3 side. Thus, the capacitive components of depletion layer for PD element generated during light receiving can be controlled to become smaller so as to speed up the response of the PD element and at the same time the high-speed operation of amplifier circuit element or operation circuit element can be realized.