The induction coil of a device that heats a toolholder (1) inductively for the tool change comprises a shielding collar (27) of magnetizable material which, firstly, concentrates the magnetic flux of the induction coil (13) in a sleeve section (5) of the toolholder (1) which holds the shaft (11) of a rotary tool with a press fit and, secondly, shields the part of the tool shaft (11) that projects out of the sleeve extension (5), in order to facilitate unclamping the tool from the toolholder (1). On its side facing the winding (19) of the induction coil (13) axially, the shielding collar (27) has an outer circumferential surface (31) which widens conically away from the sleeve extension (5) and an axial height (h) which is at least 1.5 times the diameter (d) of the tool shaft (11). The shielding collar (27) runs on all sides at a distance from a yoke shell (23) of magnetizable material which encases the winding (19) of the induction coil (13).