Provided is a concentration/separation/analysis technique with which it is possible to perform concentration and separation stably and efficiently using the MCCCE method. The present invention is an electrophoresis apparatus for concentrating/separating or analyzing ions of a substance to be concentrated/separated or analyzed by moving the ions along a migration path on which an electric field has been applied. In the electrophoresis apparatus, multiple migration paths are provided in a high thermal conductivity insulator and the electrophoresis apparatus is provided with a countercurrent-generating means for generating a flow that has a uniform speed distribution and is in the direction opposite to the ion migration direction at a speed corresponding to the ion migration speed in the solution in the migration paths. The present invention is an electrophoresis apparatus, wherein the countercurrent-generating means generates a flow that has a uniform speed distribution and is in the direction opposite to the i
