To provide an axle case manufacturing method for enhancing the reliability of a welded part, and preventing cracks during the press-forming.

In the method of manufacturing an axle case 1 for press-forming a half-split side plate member 6 from a blank 4 when manufacturing the axle case 1, each wall-increased portion 41 is provided on an end on a hole part 21 side of a part forming each straight tubular part 3 by press-forming the blank 4; the blank 4 is bent in a channel shape to respectively form flanges forming a banjo part 2 and the straight tubular portion 3; the banjo part 2 is pushed downwards, and the straight tubular portions 3, 3 upwardly so as to be bent in a V-shape; the V-shaped formed member 5 is pushed from above to bend the straight tubular portions 3, 3 downwards with an end on the banjo part 2 side as a supporting point to match the axes of the straight tubular parts 3, 3 with each other, and extend in the longitudinal direction; and the wall-increased portion is pushed toward the flanges of the straight tubular parts when the straight tubular part 3 is extended in the longitudinal direction.

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