There is provided a shutter device which is used in a camera having two image-capturing optical systems and enables a significant reduction in the number of components. Two shutter openings are formed in a shutter base. Shutter blades and a diaphragm plate are provided forward of the shutter base. When a cam pin is reciprocally moved from the position of a start point to an intermediate position or from the intermediate position to the position of an end point, the shutter blades open and close a shutter one or more times. When the cam pin is located at any position along the way from the start position to the intermediate position, the diaphragm plate is moved to a location where small diaphragm openings correspond to the shutter openings. When the cam pin is located at any position along the way from the intermediate position to the position of the endpoint, the diaphragm plate is moved to a location where open diaphragm openings correspond to the shutter openings.