To provide an energization heater capable of reducing unevenness of an axial distribution of temperatures of a metal pipe material on heating, and an energization method.SOLUTION: Electrodes 101, 102 energize a part in the circumferential direction of the outer peripheral face 14a of a metal pipe material 14 and does not energize another part in the circumferential direction of the outer peripheral face 14a of the metal pipe material 14. Accordingly, the metal pipe material 14 is arranged on the electrodes 101, 102 so that a part (first region E1) on a bend projection in the circumferential direction of the outer peripheral face 14a of the metal pipe material 14 may be energized. In the case of such an arrangement, energization is performed at the bend projection side (first region E1) of the metal pipe material 14 hard to heat because of a long current path, but energization is not performed at the recess side (first region E2) of the metal pipe material hard to heat because of a short current path.SELECTED DRAWING: Figure 4