Provided are an electrophoresis support, an electrophoresis device, and a method for manufacturing the electrophoresis support in which an isoelectric point is stably adjustable with high reproducibility. The electrophoresis support according to the present disclosure is an electrophoresis support for use in electrophoresis of a sample, and includes a substrate having, in the substrate, a plurality of gaps through which a solution containing the sample flows, and fixed acceptor or donor ions with which surfaces of the substrate are doped. The surfaces face the gaps. This configuration enables the electrophoresis support having a highly reproducible isoelectric point to be provided stably.