An apparatus for heating a workpiece, particularly a roller bearing, having low power consumption, rapid heating and low weight, includes a truncated conical contact surface for horizontal workpiece bearing, a single-layer solenoid coil underneath the contact surface, following the contact surface shape relative to its covered surface and gradient, resulting in magnetic lines of force concentrated in an internal workpiece area and a driver resonant circuit producing an alternating magnetic field in the solenoid coil. The workpiece is inductively heated quickly without requiring pushing onto a magnet yoke, because of its horizontal bearing. The planar configuration of the solenoid coil, following the contact surface shape, causes operation of the driver resonant circuit at high frequency, resulting in low power consumption. The profile of lines of force causes the magnetic field to directly enter areas to be heated on an upper workpiece surface, ensuring homogeneous workpiece heating.