To manufacture a connecting rod while keeping a treatment temperature lower to suppress the occurrence of burrs.

Rollers 40, 42 are arranged on both sides of the side face of a disc raw material 30 with their axes of rotation parallel to the direction of the thickness of the raw material 30. They are rotated 46, 47 while applying thrust 44, 45 to the side face of the raw material 30. They are moved 48, 49 in the vertically axial directions, namely, in the directions perpendicular to the side face of the raw material 30, whereby the raw material is plastically deformed to sequentially form an intermediate shape 32 and obtain a preliminary molding 34 with the outline of the connecting rod. Boring and finish correcting processed are applied to the preliminary molding 34. Thus, the connecting rod 10 is obtained which has a large end portion 12 with a supporting hole 18, a small end portion 14 with a supporting hole 20 and a pole portion 16 for joining the large end portion 12 to the small end portion 14.