To provide a spindle cooling device for machine tool, in which the contacting area is secured by sufficiently setting of a flow path for the cooling liquid, the cooling efficiency is enhanced by securing sufficient heat exchange time, and the structure around the spindle is simplified owing to provision of a ring-shaped cooling chamber at the periphery of the spindle, and further the processing is facilitated.

A spindle cooling device is composed of a spindle head 1, a spindle 2 supported rotatably at the inner circumference of the head 1 through a bearing, and a ring-shaped cooling chamber 8 furnished at the periphery of the spindle 2, wherein a cooling liquid inlet 24 is provided on one side of the cooling chamber 8, and the spindle head 1 is equipped with a cooling liquid supply passage 18 for supplying the cooling liquid to the inlet 24, while a cooling liquid outlet 30 is provided on the other side of the cooling chamber 8, and a liquid discharge passage 25 to discharge the liquid from the outlet 30 is formed in the spindle head 1.