There is provided an electrophoresis device (100) including an insulator (10) that includes: a first-separating-medium storing section (4′) for storing therein a first separating medium (4); a first opening (7) and a second opening (8) that are in communication with the first-separating-medium storing section (4′) and for defining a direction of separation on the first separating medium (4); and a third opening (9) that is covered with a penetrable insulating thin film (3), wherein the first separating medium storing section (4′) is in communication with outside via the first opening (7) and the second opening (8). There is also provided an electrophoresis apparatus including the electrophoresis device (100). This realizes an electrophoresis apparatus, and a device therefor, that enables an operator to sample separated proteins without ever making contact with the electrophoresed gel, and that can easily be used with various types of analyses, thereby improving convenience of electrophoresis.