An analog-to-digital conversion circuit includes: a clock generating circuit which generates a clock signal including a first initial period and plural normal periods following the first initial period, the first initial period being one of a high period and a low period and being a first period immediately after a reset release, each of the normal periods being one of a high period and a low period and shorter than the first initial period; and an incremental analog-to-digital converter which operates using the clock signal.