An electrophoresis chip that can be small and simple and that can analyze a sample with high accuracy is provided. The electrophoresis chip includes an upper substrate 4, a lower substrate 1, an introduction reservoir 2a, a recovery reservoir 2b and a capillary channel for sample analysis 3x. The introduction reservoir 2a and the recovery reservoir 2b are formed in the lower substrate 1. The introduction reservoir 2a and the recovery reservoir 2b are in communication with each other via the capillary channel for sample analysis 3x. The introduction reservoir 2a receives a sample to be measured. The sample is electrophoretically introduced directly into the capillary channel for sample analysis 3x by creating a potential difference between the introduction reservoir 2a and the recovery reservoir 2b, and is also analyzed in the capillary channel for sample analysis 3x during the separation of the sample while the sample is being continuously supplied.