A method of manufacturing a hub unit bearing including an outer race having a double-row outer race track (5a, 5b), a hub having a double-row inner race track (11a, 11b), and a plurality of rolling elements (4a, 4b) disposed between the outer race tracks (5a, 5b) and the inner race tracks (11a, 11b), the hub including a hub body and a double-row inner race (22a, 22b) disposed on the outside of the hub body and held by the hub body, said double-row inner race (22a, 22b) including an external inner race having an external inner race track and an internal inner race having an internal inner race track, wherein in an axial direction of the hub body, said external inner race is externally fitted to the hub body, the method comprising: a step of combining the hub body with the inner race (22a, 22b) having a hole into which the hub body is inserted in an axial direction; a step of forming a caulking portion for the inner race (22a, 22b) in the hub body by applying an axial load to a shaft end of the hub body, said caulking portion forming step including a first step and a second step, wherein the first step is a step of processing a cylindrical portion provided in the axial inner end portion of the hub body into a caulking portion intermediate body, with a predetermined load, by pressing a swaging forming die, that swings and rotates about a center axis of the hub body against the axial inner end portion of the hub body, wherein the second step of processing said caulking portion intermediate body into the caulking portion, by applying an adjusted load based on at least one of (a) first information acquired before applying the predetermined load and (b) second information acquired while applying the predetermined load, wherein in the second step, the caulking portion intermediate body is processed into the caulking portion by pressing a second swaging forming die, that swings and rotates about a center axis of the hub body against the axial inner end portion of the hub body, wherein said first information includes at least one of a (i) fitting allowance between a fitting surface portion of the hub body and an internal inner race and the external inner race, (ii) a press-fitting load (Fp) for press-fitting the internal inner race and the external inner race into the fitting surface portion, and (iii) a bearing axial gap (Δa) which is internal gap of the bearing in the axial direction before forming the staking portion, wherein said second information is (iv) an axial load applied from the forming die to the axial inner end portion of the hub body, (v) a forming rotation torque (Ts) for swinging and rotating the forming die, and (vi) an axial movement speed (Vs) of the forming die. a step of combining the hub body with the inner race (22a, 22b) having a hole into which the hub body is inserted in an axial direction; a step of forming a caulking portion for the inner race (22a, 22b) in the hub body by applying an axial load to a shaft end of the hub body, said caulking portion forming step including a first step and a second step, wherein the first step is a step of processing a cylindrical portion provided in the axial inner end portion of the hub body into a caulking portion intermediate body, with a predetermined load, by pressing a swaging forming die, that swings and rotates about a center axis of the hub body against the axial inner end portion of the hub body, wherein the second step of processing said caulking portion intermediate body into the caulking portion, by applying an adjusted load based on at least one of (a) first information acquired before applying the predetermined load and (b) second information acquired while applying the predetermined load, wherein in the second step, the caulking portion intermediate body is processed into the caulking portion by pressing a second swaging forming die, that swings and rotates about a center axis of the hub body against the axial inner end portion of the hub body, wherein said first information includes at least one of a (i) fitting allowance between a fitting surface portion of the hub body and an internal inner race and the external inner race, (ii) a press-fitting load (Fp) for press-fitting the internal inner race and the external inner race into the fitting surface portion, and (iii) a bearing axial gap (Δa) which is internal gap of the bearing in the axial direction before forming the staking portion, wherein said second information is (iv) an axial load applied from the forming die to the axial inner end portion of the hub body, (v) a forming rotation torque (Ts) for swinging and rotating the forming die, and (vi) an axial movement speed (Vs) of the forming die.