To provide a blade drive device capable of suppressing the increase in number of components while suppressing the bounding of blades, and an optical apparatus including the blade drive device. A blade drive device 10 includes a partition plate 21 having an opening 22, blades 31a to 34a, 31b to 34b which are expanded in a state where the opening 22 is closed and which overlap one another in a state where the opening 22 is opened, and a first regulating portion 23A and a second regulating portion 24A integrally formed with the partition plate 21, on which the blades 31a, 31b abut when being expanded. An optical apparatus includes the blade drive device 10.