A fixing device includes a heating rotating member that generates heat by induction heating; an induction coil that generates magnetic flux for induction heating; and a magnetic member core section forming a magnetic path and including a first core section, a second core section, a magnetic flux shielding member, and third core sections. The magnetic flux shielding member is disposed at a side of an end portion of the first core section opposite to the second core section and separated from the end portion, and disposed at a position that is separated from the outer surface of the heating rotating member by a separation distance. The third core sections are disposed at a side of the magnetic flux shielding member facing the end portion of the first core section. At least one of the third core sections is movable to a first position and to a second position.