1. A capillary electrophoresis apparatus having: an exchangeable capillary; an optical irradiation system which irradiates the capillary with excitation light; and an optical detection system which includes a wavelength dispersion device and a two-dimensional detector, the wavelength dispersion device dispersing fluorescent light from the capillary, the two-dimensional detector detecting a fluorescence spectrum image acquired from the wavelength dispersion device, wherein the optical detection system has a multi-bandpass filter having a plurality of discontinuous wavelength transmission regions.