A heater substrate has an insulating substrate having a first surface and a second surface on the opposite side relative to the first surface and at least one heating element of spiral shape including plural heater wire pieces and positioned in or on the insulating substrate. The heating element of spiral shape has at least one adjustment section including a turn of all or some of the plural heater wire pieces. The plural heater wire pieces include a first heater wire piece and a second heater wire piece adjacent to the inner side of the first heater wire piece. In the adjustment section, the length of the first heater wire piece is smaller than the length of the second heater wire piece.