In an automatic feeder and an image acquiring apparatus, a cover is rotatably connected to a body through a first pin and openable and closable with respect to the body. A roller gear rotates a transporting roller to transport a sheet. An actuating member is attached to the first pin and driven by rotation of the first pin. A middle gear, displaceable by the actuating member, is selectively engaged with a power-output gear and the roller gear so as to transmit a power to the roller gear. An actuating member moves the middle gear to be engaged with the power-output gear and the roller gear when the cover is closed upon the body, and moves the middle gear to be disengaged from at least one of the power-output gear and roller gear when the cover is opened.