Photoelectric conversion device includes first substrate having blocks each including photoelectric converters, and second substrate having at least part of processing circuit for reading out signals from the photoelectric converters. The processing circuit drives driving signal lines for driving the photoelectric converters. The driving signal lines include first signal lines each arranged in the first substrate and commonly assigned to at least two blocks arranged in row direction of the blocks and second signal lines each individually assigned to one block of the blocks. The processing circuit includes transmission lines and selection circuits each corresponding to one second signal line of the second signal lines. Each selection circuit selects one driving signal from driving signals supplied to the transmission lines, and supplies the selected driving signal to the corresponding second signal line of the second signal lines.