Certain embodiments provide a fuser including a cylindrical fixing belt, a heating member, an auxiliary heat generating member, a plurality of heat pipes, a pressurizing pad, and a pressurizing roller. The heating member heats the fixing belt. The auxiliary heat generating member auxiliary heats the fixing belt. The plural heat pipes are sparsely arranged in the center in the longitudinal direction of the auxiliary heat generating member and more densely arranged at the ends in the longitudinal direction of the auxiliary heat generating member than in the center. The pressurizing pad is arranged on the inside of the fixing belt. The pressurizing roller is arranged in contact with the outer circumference of the fixing belt. The pressurizing roller presses the fixing belt against the pressurizing pad.