A seal structure for an electromagnet lead wire, comprising: an annular yoke including an annular groove configured to store an exciting coil; a wiring hole extending in an axial direction of the yoke, opening to a bottom of the annular groove and an outside of the seal structure and configured to pass a lead wire connected to the exciting coil; an insulating resin configured to seal the exciting coil and a connecting portion between the exciting coil and the lead wire; and a seal member made of an elastic material and arranged in the wiring hole in a state in which the lead wire is liquid-tightly fitted, wherein the wiring hole includes: a first hole portion (35, 82) including one end and the other end opening to the outside of the seal structure; and a second hole portion (33, 83) connected to the one end of the first hole portion (35, 82) and having an opening width larger than an opening width of the first hole portion (35, 82), the insulating resin extends from an inside of the annular groove up to the second hole portion (33, 83), and includes a projecting portion including a distal end face orthogonal to the axial direction in the second hole portion (33, 83), the seal member includes: a columnar portion inserted into the first hole portion (35, 82); a plate-shaped portion extending in a direction orthogonal to the axial direction in the second hole portion (33, 83); and a through hole extending through the columnar portion and the plate-shaped portion and configured to receive the lead wire, and the plate-shaped portion is sandwiched and compressed between the distal end face of the projecting portion and a hole wall surface (24a, 83a) extending from a boundary between the first hole portion (35, 82) and the second hole portion (33, 83) in the direction orthogonal to the axial direction, characterized in that the plate-shaped portion of the seal member includes: a disc portion connected to the columnar portion and projecting from the columnar portion in the direction orthogonal to the axial direction; and a seal portion, projecting from both sides of the disc portion in the axial direction and having a circular section with an outer diameter in the axial direction larger than a thickness of the disc portion. an annular yoke including an annular groove configured to store an exciting coil; a wiring hole extending in an axial direction of the yoke, opening to a bottom of the annular groove and an outside of the seal structure and configured to pass a lead wire connected to the exciting coil; an insulating resin configured to seal the exciting coil and a connecting portion between the exciting coil and the lead wire; and a seal member made of an elastic material and arranged in the wiring hole in a state in which the lead wire is liquid-tightly fitted, wherein the wiring hole includes: a first hole portion (35, 82) including one end and the other end opening to the outside of the seal structure; and a second hole portion (33, 83) connected to the one end of the first hole portion (35, 82) and having an opening width larger than an opening width of the first hole portion (35, 82), a first hole portion (35, 82) including one end and the other end opening to the outside of the seal structure; and a second hole portion (33, 83) connected to the one end of the first hole portion (35, 82) and having an opening width larger than an opening width of the first hole portion (35, 82), the insulating resin extends from an inside of the annular groove up to the second hole portion (33, 83), and includes a projecting portion including a distal end face orthogonal to the axial direction in the second hole portion (33, 83), the seal member includes: a columnar portion inserted into the first hole portion (35, 82); a plate-shaped portion extending in a direction orthogonal to the axial direction in the second hole portion (33, 83); and a through hole extending through the columnar portion and the plate-shaped portion and configured to receive the lead wire, and a columnar portion inserted into the first hole portion (35, 82); a plate-shaped portion extending in a direction orthogonal to the axial direction in the second hole portion (33, 83); and a through hole extending through the columnar portion and the plate-shaped portion and configured to receive the lead wire, and the plate-shaped portion is sandwiched and compressed between the distal end face of the projecting portion and a hole wall surface (24a, 83a) extending from a boundary between the first hole portion (35, 82) and the second hole portion (33, 83) in the direction orthogonal to the axial direction, characterized in that the plate-shaped portion of the seal member includes: a disc portion connected to the columnar portion and projecting from the columnar portion in the direction orthogonal to the axial direction; and a seal portion, projecting from both sides of the disc portion in the axial direction and having a circular section with an outer diameter in the axial direction larger than a thickness of the disc portion. a disc portion connected to the columnar portion and projecting from the columnar portion in the direction orthogonal to the axial direction; and a seal portion, projecting from both sides of the disc portion in the axial direction and having a circular section with an outer diameter in the axial direction larger than a thickness of the disc portion.