Swaging device and swaging method

Provided is a swaging device including: an upper anvil that is disposed in a state in which the upper anvil faces an end surface of a head of a rivet; a lower anvil that is disposed in a state in which the lower anvil faces an end surface of a shaft portion of the rivet; and a pressurizing mechanism that generates a pressurizing force of causing a distance between the upper anvil and the lower anvil along an axial line to decrease and plastically deforms the rivet, in which an end surface of the upper anvil includes a bottom surface that perpendicularly intersects the axial line X and a support surface that has a projecting length in a direction of the axial line with respect to the bottom surface gradually increasing from an inner circumferential side toward an outer circumferential side in the radial direction formed therein, and an inclination angle of the support surface is smaller than an inclination angle of the inclined surface of the rivet by a predetermined angle.