To realize a body surrounding solenoid-type body heating device with small coil impedance which can generate a magnetic flux of predetermined density to one part of the living body near the affected area in the solenoid coil, a body heating device 10 includes a cylindrical solenoid coil 17 in which the body can be inserted easily, a high-frequency power supply 11 to drive the solenoid coil, and a body holder 15 which can be inserted easily in the solenoid coil 17. In the body heating device 10, an across-body direction cross section of the solenoid coil 17 has an arched-shape over a half of the solenoid coil 17 in the peripheral direction and a straight-lined shape in the rest, and a secondary solenoid coil 21 with shorter length and coiled more densely than the solenoid coil 17 is inserted in the solenoid coil 17. A magnetic core 40 which can be inserted easily in the solenoid coil 17 is installed on the body holder 15.