A capillary array electrophoresis which can measure fluorescence of a number of capillaries at a time with high sensitivity and can automatically analyze a sample sequentially. An end edge as a sample dissolution edge of a number of capillaries is connected to a polymer filling block having a mechanism of filling the polymer as an isolation medium inside a capillary. Fluorescence irradiated from an edge surface of an end edge portion of the capillary is detected through a detection window in which distance between an external surface and a detection surface is smaller than focal distance of an optical lens closest to a detection flat surface.