An image-taking apparatus is disclosed which has a mirror drive mechanism with a small number of constituent parts, easy assembly. The image-taking apparatus has a mirror movable to a first position in an optical path and to a second position outside the optical path, a first biasing member biasing the mirror from the second position to the first position, a second biasing member biasing the mirror from the first position to the second position, a holding member holding the first biasing member in a charged state, a first cam having a charge portion for charging the second biasing member and a release portion for releasing the charge of the second biasing member, a second cam releasing the holding by the holding member, and a motor driving both of the first and second cams only in one direction.