A blade driving device includes: a board including an optical path opening; first and second blades moving toward and away from the optical path opening; first and second transmitting portions driving the first and second blades; and first and second drive sources respectively driving the first and second transmitting portions, wherein the first and second transmitting portions respectively include first and second drive pins, and the first blade includes an engagement slot engaging one of the first and second drive pins and is attached to the first and the second transmitting portions to be rotatable about the other of the first and second drive pins.