To provide an aperture device with improved aperture accuracy and to provide an optical apparatus including the same.

The aperture device includes: a substrate having an aperture; a step motor capable of stopping for every predetermined rotation angle; an output member having a first pin and a second pin and rotating in a predetermined range by the step motor; and first and second blades that are engaged with the first and second pins respectively to be driven by the output member, linearly move in the mutually opposite directions to overlap on the aperture, and adjust the aperture area of the aperture. When a virtual line segment that passes through the rotation center of the output member and extends in the moving direction of the blades is defined as an X axis, an angle formed between the X axis and a direction line segment formed by connecting a rotation center when the aperture area is minimized to the first pin is -20° to +30°.