An imaging optical system includes an objective lens configured to focus light having a first wavelength band and light having a second wavelength band, an optical shutter module configured to reflect the light having the first wavelength band, which is focused by the objective lens, without modulating the light having the first wavelength band and to modulate the light having the second wavelength band, which is focused by the objective lens, and reflect the modulated light having the second wavelength band, and an image sensor configured to respectively sense the light having the first wavelength band and the modulated light having the second wavelength band, which are reflected by the optical shutter module, and to output a first image signal with respect to the light having the first wavelength band and a second image signal with respect to the modulated light having the second wavelength band.