This
semiconductor light-receiving element (1) is provided with: a substrate (10); a
semiconductor laminated part (20) that is formed on the substrate (10); and a first
electrode (40) and a second
electrode (50) that are electrically connected to the
semiconductor laminated part (20). The semiconductor laminated portion (20) includes a light
absorption layer (24) including InGaAs and including a first region (24a) of a first
conductivity type, a first semiconductor layer (S1) located between the substrate (10) and the light
absorption layer (24), a second semiconductor layer (S2) located on the opposite side of the substrate (10) with respect to the light
absorption layer (24), and a first region (24a) of a second
conductivity type formed of InP, InGaAsP, InAsP, InGaAsP, InAsP, InGaAsP, InAsP, InGaAsP, InAsP, InGaAsP, InGaAsP, InAsP, InGaAsP, InGaAsP, InAsP, InGaAsP, InGaAsP, InGaAsP, InGaAsP, InGaAsP, InGaAsP, and a
capacitance reduction layer (23) of the first
conductivity type, which has an arbitrary configuration of AlInGaAs and is positioned between the light absorption layer (24) and one of the first semiconductor layer (S1) and the second semiconductor layer (S2), and which has a carrier concentration of 5 * 1015 cm-3 or less and is higher than the carrier concentration of the first region (24a) of the light absorption layer (24). The
band gap of the
capacitance reduction layer (23) is larger than the
band gap of the light absorption layer (24).