A manufacturing method for a connection between an electromagnetic crimp terminal and an electric wire, the electric wire including a conductor portion whose periphery is covered with an insulation portion, and the electromagnetic crimp terminal has a terminal plate including a crimped portion that can be crimped onto the conductor portion of the electric wire, the manufacturing method comprising: preparing the terminal plate including a rectangular flat plate portion to be the crimped portion; forming the flat plate portion into a cylindrical portion, and overlapping a vicinity of a first side edge of the cylindrical portion and a vicinity of a second side edge of the cylindrical portion each other, so that the cylindrical portion configure an annular conductive circuit before reducing a diameter of the cylindrical portion; inserting an exposed portion, which is a part of the conductor portion of the electric wire exposed by peeling off a part of the insulation portion, into the cylindrical portion; inserting the cylindrical portion into which the exposed portion is inserted into a discharge coil having a substantially C-shaped cross section; causing a discharge current to instantaneously flow through the discharge coil, and reducing the diameter of the cylindrical portion by an electromagnetic force based on an induced current and an induced magnetic field, and conductively crimping the crimped portion onto the exposed portion, wherein the induced current is generated in the cylindrical portion due to the discharge current, and the induced magnetic field is generated between the discharge coil and the cylindrical portion due to the induced current, wherein the first side edge is in contact with an outer surface of the cylindrical portion near the second side edge, before reducing the diameter of the cylindrical portion, and/or the second side edge is in contact with an inner surface of the cylindrical portion near the first side edge, before reducing the diameter of the cylindrical portion. preparing the terminal plate including a rectangular flat plate portion to be the crimped portion; forming the flat plate portion into a cylindrical portion, and overlapping a vicinity of a first side edge of the cylindrical portion and a vicinity of a second side edge of the cylindrical portion each other, so that the cylindrical portion configure an annular conductive circuit before reducing a diameter of the cylindrical portion; inserting an exposed portion, which is a part of the conductor portion of the electric wire exposed by peeling off a part of the insulation portion, into the cylindrical portion; inserting the cylindrical portion into which the exposed portion is inserted into a discharge coil having a substantially C-shaped cross section; causing a discharge current to instantaneously flow through the discharge coil, and reducing the diameter of the cylindrical portion by an electromagnetic force based on an induced current and an induced magnetic field, and conductively crimping the crimped portion onto the exposed portion, wherein the induced current is generated in the cylindrical portion due to the discharge current, and the induced magnetic field is generated between the discharge coil and the cylindrical portion due to the induced current, wherein the first side edge is in contact with an outer surface of the cylindrical portion near the second side edge, before reducing the diameter of the cylindrical portion, and/or the second side edge is in contact with an inner surface of the cylindrical portion near the first side edge, before reducing the diameter of the cylindrical portion.