A solid-state imaging device comprising: a plurality of photodiodes (PD1, PD2, PD3) having each a pn junction located at different depths in a unit pixel area of a substrate, the substrate having two oppositely facing faces, wherein the plurality of photodiodes comprises first, second and third photodiodes (PD1, PD2, PD3) with a pn-junction being located at a first depth, a second depth and a third depth from one face of the substrate, respectively, the first depth being smaller than the second depth and the second depth being smaller than the third depth, a plurality of vertical transistors (Tr1, Tr2, Tr3) in the unit pixel area, the plurality of vertical transistors comprising gate portions (3033, 3037, 3042, 3034, 3039, 3040, 3044) for reading signal charges obtained by photoelectric conversion in the plurality of photodiodes (PD1, PD2, PD3), the gate portions (3033, 3037, 3042, 3034, 3039, 3040, 3044) being located in a depth direction from the one face of the substrate, characterized in that each gate portion (3033, 3037, 3042, 3034, 3039, 3040, 3044) has a gate electrode (3033, 3037, 3042) which extends from the one face of the substrate to a depth corresponding to the pn junction of a different one of the plurality of photodiodes (PD1, PD2, PD3), wherein each gate portion (3033, 3037, 3042, 3034, 3039, 3040, 3044) reaches the pn junction of the respective photodiode (PD1, PD2, PD3), the plurality of vertical transistors further comprises first, second and third vertical transistors (Tr1, Tr2, Tr3) with gate portions extending from the one face of the substrate to the first depth, the second depth and the third depth, respectively, wherein portions of a charge accumulation region) of the first photodiode which touch the second vertical transistor and portions of charge accumulation regions (3025, 3027) of the first and second photodiodes (PD1, PD2) which touch the third vertical transistor are formed of a semiconductor layer having the conductive type opposite to the conductive type of the charge accumulation region (3025, 3027). a plurality of photodiodes (PD1, PD2, PD3) having each a pn junction located at different depths in a unit pixel area of a substrate, the substrate having two oppositely facing faces, wherein the plurality of photodiodes comprises first, second and third photodiodes (PD1, PD2, PD3) with a pn-junction being located at a first depth, a second depth and a third depth from one face of the substrate, respectively, the first depth being smaller than the second depth and the second depth being smaller than the third depth, a plurality of vertical transistors (Tr1, Tr2, Tr3) in the unit pixel area, the plurality of vertical transistors comprising gate portions (3033, 3037, 3042, 3034, 3039, 3040, 3044) for reading signal charges obtained by photoelectric conversion in the plurality of photodiodes (PD1, PD2, PD3), the gate portions (3033, 3037, 3042, 3034, 3039, 3040, 3044) being located in a depth direction from the one face of the substrate, characterized in that each gate portion (3033, 3037, 3042, 3034, 3039, 3040, 3044) has a gate electrode (3033, 3037, 3042) which extends from the one face of the substrate to a depth corresponding to the pn junction of a different one of the plurality of photodiodes (PD1, PD2, PD3), wherein each gate portion (3033, 3037, 3042, 3034, 3039, 3040, 3044) reaches the pn junction of the respective photodiode (PD1, PD2, PD3), the plurality of vertical transistors further comprises first, second and third vertical transistors (Tr1, Tr2, Tr3) with gate portions extending from the one face of the substrate to the first depth, the second depth and the third depth, respectively, wherein portions of a charge accumulation region) of the first photodiode which touch the second vertical transistor and portions of charge accumulation regions (3025, 3027) of the first and second photodiodes (PD1, PD2) which touch the third vertical transistor are formed of a semiconductor layer having the conductive type opposite to the conductive type of the charge accumulation region (3025, 3027).