To make a chip type electrophoresis device able to analyze even a small quantity of sample.

An electrophoretic chip 21 comprises a pair of transparent planar base materials. On the surface of one base material, a sample introduction passage 13 and a separation passage 15 crossing each other are formed. On the other base material, a separation buffer waste 17a, a separation buffer reservoir 17c, a loading buffer reservoir 17s' and a loading buffer waste 17w are formed by through holes on positions corresponding to the ends of the passage 13, 15. In addition, a sample reservoir 22 for injecting the sample is formed on the position different from the reservoir 17s' as a through hole on the sample introduction passage 13. Electrodes 4, 6, 2, 8 are arranged on the reservoirs 17c, 17s' and the wastes 17a, 17w, and are not arranged on the sample reservoir 22.