Abstract: A thermotherapy device comprises a cup-like housing (1) having a heat radiation opening (1a), a rod-like electric heater (2) contained in the housing (1) with the leading end thereof being directed toward the heat radiation opening (1a), and a controller (3) for supplying power to the electric heater (2) and controlling the amount of heat generation from the electric heater (2). Since the electric heater (2) is employed, replacement of a combustion rod and handling of combustion ash are not required, and the thermotherapy device can be used even in bed. Moreover, power is supplied to the electric heater (2) while regulating the amount of heat generation by means of controller (3). Accordingly, the skin (S) can be heated in safety to a high temperature of 55 to 60 degrees C., and an affected part (A) located on or under the skin (S) can be exposed to a sufficiently high temperature for treatment of cancer.