A crimping die, comprising: a first die formed with a concave die surface for constraining a cylindrical wire crimping portion of a terminal fitting; and a second die formed with a convex die surface paired with the concave die surface; wherein: a width of a recess on the concave die surface and that of a projection on the convex die surface are equal to an outer diameter of the wire crimping portion; the wire crimping portion is sandwiched between the concave die surface and the convex die surface to be compressed and deformed, whereby the wire crimping portion and the wire inserted into the cylindrical interior of the wire crimping portion are crimped and fixed, a bottom surface of the recess includes a first inclined surface part inclined in a depth direction of the recess toward an end part in the length direction; and an upper end surface of the projection includes a second inclined surface part inclined in a direction opposite to a projecting direction of the projection toward an end part in the length direction; characterized in that each of the first and second inclined surface parts (45, 55) is shaped such that an angle of inclination discontinuously changes to increase toward the end part; the first die includes a first protrusion standing on the bottom surface of the recess on the concave die surface and extending along a length direction perpendicular to a width direction of the recess; and the second die includes a second protrusion standing on the upper end surface of the projection on the convex die surface and extending along a length direction perpendicular to a width direction of the projection. a first die formed with a concave die surface for constraining a cylindrical wire crimping portion of a terminal fitting; and a second die formed with a convex die surface paired with the concave die surface; wherein: a width of a recess on the concave die surface and that of a projection on the convex die surface are equal to an outer diameter of the wire crimping portion; the wire crimping portion is sandwiched between the concave die surface and the convex die surface to be compressed and deformed, whereby the wire crimping portion and the wire inserted into the cylindrical interior of the wire crimping portion are crimped and fixed, a bottom surface of the recess includes a first inclined surface part inclined in a depth direction of the recess toward an end part in the length direction; and an upper end surface of the projection includes a second inclined surface part inclined in a direction opposite to a projecting direction of the projection toward an end part in the length direction; characterized in that each of the first and second inclined surface parts (45, 55) is shaped such that an angle of inclination discontinuously changes to increase toward the end part; the first die includes a first protrusion standing on the bottom surface of the recess on the concave die surface and extending along a length direction perpendicular to a width direction of the recess; and the second die includes a second protrusion standing on the upper end surface of the projection on the convex die surface and extending along a length direction perpendicular to a width direction of the projection. a width of a recess on the concave die surface and that of a projection on the convex die surface are equal to an outer diameter of the wire crimping portion; the wire crimping portion is sandwiched between the concave die surface and the convex die surface to be compressed and deformed, whereby the wire crimping portion and the wire inserted into the cylindrical interior of the wire crimping portion are crimped and fixed, a bottom surface of the recess includes a first inclined surface part inclined in a depth direction of the recess toward an end part in the length direction; and an upper end surface of the projection includes a second inclined surface part inclined in a direction opposite to a projecting direction of the projection toward an end part in the length direction; characterized in that each of the first and second inclined surface parts (45, 55) is shaped such that an angle of inclination discontinuously changes to increase toward the end part; the first die includes a first protrusion standing on the bottom surface of the recess on the concave die surface and extending along a length direction perpendicular to a width direction of the recess; and the second die includes a second protrusion standing on the upper end surface of the projection on the convex die surface and extending along a length direction perpendicular to a width direction of the projection.