A connection unit (1, 2, 3, 4, 5, 6, 6a), which is magnetically connectable to other connection units (1, 2, 3, 4, 5, 6, 6a) into an assembly, comprising: a body (11, 11a) having a substantially flat plate shape and peripheral edges; a plurality of magnets, at least one of which being disposed on each side of the peripheral edges of the body (11, 11a); and a plurality of electrode terminals (13, 14, 43, 44), at least three of which being disposed on the each side of the peripheral edges of the body (11, 11a), wherein an outer surface of the each side of the body (11, 11a) has a curved surface which curves in a thickness direction or a surface having a polygonal cross section, the electrode terminals (13, 14, 43, 44) are disposed along the curved surface or the surface having the polygonal cross section of the outer surface, and the at least three electrode terminals (13, 14, 43, 44) disposed on the each side of the peripheral edges of the body (11, 11a) comprise either: one positive electrode terminal (13, 43) and two negative electrode terminals (14, 44), the positive electrode terminal (13, 43) being disposed at a center of the respective side of the peripheral edges of the body (11, 11a) and the negative electrode terminals (14, 44) being disposed line-symmetrical about a perpendicular line perpendicular to and crossing the center of the respective side of the body (11, 11a), or one negative electrode terminal (14, 44) and two positive electrode terminals (13, 43), the negative electrode terminal (14, 44) being disposed at the center of the respective side of the peripheral edges of the body (11, 11a) and the positive electrode terminals (13, 43) being disposed line-symmetrical about the perpendicular line perpendicular to and crossing the center of the respective side of the body (11, 11a). a body (11, 11a) having a substantially flat plate shape and peripheral edges; a plurality of magnets, at least one of which being disposed on each side of the peripheral edges of the body (11, 11a); and a plurality of electrode terminals (13, 14, 43, 44), at least three of which being disposed on the each side of the peripheral edges of the body (11, 11a), wherein an outer surface of the each side of the body (11, 11a) has a curved surface which curves in a thickness direction or a surface having a polygonal cross section, the electrode terminals (13, 14, 43, 44) are disposed along the curved surface or the surface having the polygonal cross section of the outer surface, and the at least three electrode terminals (13, 14, 43, 44) disposed on the each side of the peripheral edges of the body (11, 11a) comprise either: one positive electrode terminal (13, 43) and two negative electrode terminals (14, 44), the positive electrode terminal (13, 43) being disposed at a center of the respective side of the peripheral edges of the body (11, 11a) and the negative electrode terminals (14, 44) being disposed line-symmetrical about a perpendicular line perpendicular to and crossing the center of the respective side of the body (11, 11a), or one negative electrode terminal (14, 44) and two positive electrode terminals (13, 43), the negative electrode terminal (14, 44) being disposed at the center of the respective side of the peripheral edges of the body (11, 11a) and the positive electrode terminals (13, 43) being disposed line-symmetrical about the perpendicular line perpendicular to and crossing the center of the respective side of the body (11, 11a). one positive electrode terminal (13, 43) and two negative electrode terminals (14, 44), the positive electrode terminal (13, 43) being disposed at a center of the respective side of the peripheral edges of the body (11, 11a) and the negative electrode terminals (14, 44) being disposed line-symmetrical about a perpendicular line perpendicular to and crossing the center of the respective side of the body (11, 11a), or one negative electrode terminal (14, 44) and two positive electrode terminals (13, 43), the negative electrode terminal (14, 44) being disposed at the center of the respective side of the peripheral edges of the body (11, 11a) and the positive electrode terminals (13, 43) being disposed line-symmetrical about the perpendicular line perpendicular to and crossing the center of the respective side of the body (11, 11a).