The invention relates to a shrinking device for shrinking a rotary tool into a central receiving opening of a toolholder which holds said rotary tool in a press fit. The device an induction heating device for thermally expanding the toolholder in the area of the receiving opening. A cooling device with at least one cooling collar which can be placed on the toolholder, in physical contact with the same, and through which a liquid coolant can flow, is provided for cooling the receiving opening area of the toolholder. This liquid cooling considerably reduces the overall time span needed for the shrinking process.