To provide an apparatus reducing a magnetic field fluctuating in a physical portion of a user to a World Health Organization recommendation criterion of 0.3 μT or less by a comparatively inexpensive and simple method, and as a result, causing less cases of childhood leukemia by providing a composition mutually neutralizing generated extremely low frequency magnetic fields in a heater using electricity.

A heater element is cylindrically shaped, and a conductive wire is arranged inside. Or, a conductive wire is arranged in parallel with a wired heater element, and they are serially connected to feed substantially the same alternating currents in opposite directions. As a result, the magnetic field affecting the user is reduced to 0.3 μT or less by mutually neutralizing the magnetic fields generated from the heater element and the conductive wire.