Abstract: A shutter apparatus is provided wherein openings for defining a secondary aperture are formed in respective shutter blades, such that an amount of light transmitted through the secondary aperture is detected, and the drive force for driving the shutter blades is changed so that the amount of the received amount increases in the opening stroke according to a predetermined function. When the integrated quantity of the received light reaches a threshold value, the movement of the shutter blades is reversed, and the shutter speed is determined based on the integrated light quantity obtained upon completion of shifting to the closing stroke. Thus, variations in the exposure amount that occur upon reversal of the shutter blades are canceled in the closing stroke.