ELECTROPHORESIS METHOD, ELECTROPHORESIS SYSTEM, AND CONTAINER VESSEL FOR ELECTROPHORESIS

An electrophoresis method includes a support body preparation step of preparing a support body that includes a first end portion on one side in a first direction and a second end portion on the other side, and forms a flow path of a sample between the first end portion and the second end portion; a sample loading step of loading the sample with respect to the support body; and a voltage application step of applying voltage to form a potential difference in the flow path and thus to cause an object to move in the flow path to a second end portion side of the first direction. The support body includes a concentrating portion, which concentrates the object, between the first end portion and the second end portion. When an area of a cut section of the flow path when cut at a predetermined position in the first direction along a plane orthogonal to the first direction is a flow path cross-sectional area, a flow path cross-sectional area of the concentrating portion is smaller than a flow path cross-sectional area in a first region closer to a first end portion side than the concentrating portion, and a flow path cross-sectional area of a second region closer to the second end portion side than the concentrating portion is larger than the flow path cross-sectional area of the concentrating portion.