A blade driving device according to the present invention includes: a substrate having an aperture; a first blade and a second blade which open and close the aperture; a first driving member which drives the first blade; a second driving member which drives the second blade; a first actuator which operates the first driving member; and a second actuator which operates the second driving member, wherein the first actuator and the second actuator extend along a first direction which intersects an axial direction of the aperture on a primary surface of the substrate and are arranged in a second direction which intersects the axial direction and the first direction.