A shaft cooler (1) for a tool motor spindle (2), which has a rotating shaft (3), a static lance (4), and at least one coolant loop (7), which comprises a coolant inlet (5) and a coolant outlet (6), said shaft cooler being implemented such that the flow of the coolant from the static lance (4) into the rotating shaft (3) is performed via a flow path that includes radially-extending cooling holes (31) to cause the coolant to flow from a radially inside location to a radially outside location.