A cutting tool device for a machine tool having a cutting tool (2) for cutting a plane fixed to the tip end of a rotating shaft (1) and provided with a suction cover (10) covering airtightly the surrounding portions except for a tip face (a), of the cutting tool (2), wherein a hood (19) is attached to the tip opening edge of the suction cover (10) so as to further extend forward therefrom and to be displaceable longitudinally within a limited range, and an urging means (24) for urging the hood (19) forward is provided, whereby chips (w1) produced by the cutting tool (2) can be positively sucked and discharged when the tool is used in any of a roughing step and a finishing step.