An embodiment discloses a heating rod comprising: a ceramic substrate; and a heat-radiating element that is arranged in the ceramic substrate, wherein the ratio of the thickness of the ceramic substrate to the thickness of the heat-radiating element is between 1:2 and 1:50. The embodiment discloses a heater comprising: a case; a heat-radiating module that is arranged inside the case; and a power module that is electrically connected to the heat-radiating module, wherein the power module includes a substrate part, a heat sink that is connected to the substrate part, and a ventilation part through which a fluid flows in and out to/from the heat sink.