An induction heating device for a metal strip, the induction heating device including: an induction coil that is provided on one strip thickness direction side or on both strip thickness direction sides of a metal strip that travels along its length direction, and that induces an induction current in the metal strip when a primary current is passed through the induction coil, the induction current configuring a closed loop as viewed from the strip thickness direction of the metal strip; plural magnetic cores that face the metal strip in the strip thickness direction and that are disposed at a specific position separated from the metal strip by a specific distance so as to concentrate magnetic flux generated by the induction coil; and a moving mechanism that is coupled to the magnetic cores, and that moves the magnetic cores so as to increase or decrease a disposed number of the magnetic cores at the specific position disposed side-by-side along a strip width direction of the metal strip.