A blade driving device is smaller and has fewer components. A blade driving device includes a base including a support shaft extending frontward, a cover having an opening, a blade located in a blade chamber defined between the base and the cover, and an actuator that moves the blade between a closing position to cover the opening and an opening position to uncover the opening. The cover covers a front of the base. The actuator includes a lever connected to the blade. The lever includes a lever body rotatable about the support shaft in the base, a connector connecting the lever body and the blade, and a protrusion protruding from the lever body frontward beyond the blade and facing the cover.