An imaging apparatus capable of suppressing deterioration of image qualities and output properties is provided having one or more output circuits in series and a buffer circuit 6, and processing luminance signals from photodetectors to output image information, the buffer circuit performing impedance conversion on signals outputted from a final output circuit of the one or more output circuits, the final output circuit being a source follower circuit that has an active element and a current source circuit 5 which is inserted between a source terminal of the active element and a reference voltage terminal, wherein the current source circuit and the buffer circuit 6 are external to a solid-state image sensor 1 having the photodetectors, and a main part of the current source circuit 5 and a main part of the buffer circuit 6 are in a single package.