Abstract: In the case where a heater main body (1) is bent so as to be wound around a subject to be heated such as a water pipe, etc., a heater can stably heats the subject to be heated. A plurality of heating elements (2), which are composed of ceramics as positive-characteristic thermistors and have electrodes on both sides of the heating elements, are sealed along a lengthwise direction of the heater main body (1) with flexibility and electrical insulation at intervals. Pairs of feeders (3) for feeding electricity to the heating elements (2) are provided to the heater main body (1). A holder (5) having electrical conductivity is provided into the heater main body (1) so as to connect the heating elements (2) to the feeders (3) and retain them. The holder (5) reduces faulty electrical connection between the feeders (3) and the heating elements (2), and thus the heat generation by the heating elements (2) can be stabilized.