The illumination apparatus includes a first light source and a second light source configured to generate light in wavelength bands required for at least two illumination modes; a dichroic mirror configured to transmit light in a predetermined band from the first light source, to transmit light in the predetermined band from the second light source while reflecting light that is outside the predetermined band in the direction of the optical axis of light from the first light source, and to combine the light from the first light source and the light from the second light source; and a control unit configured to control the illumination states of the first light source and the second light source.