DRILLING TOOL WITH SLEEVE

PROBLEM TO BE SOLVED: To prevent cutting chips from falling through a cutting hole from outer circumferences of a front end-side cutting section and base end-side cutting section and remaining on top of a cutting object, because an inner circumferential surface of the cutting hole cut by the base end-side cutting section of a cutter 7 has an identical inner diameter with an inner circumferential surface of a sleeve, matching with each other.SOLUTION: A rotary blade body 4 is moved toward an axis line 1a of the sleeve 1 by an elastic force of a compression coil spring 19 to deeply insert the front end-side cutting section 9 and base-end side cutting section 10 of the cutter 7 into the inside of a front-end opening 2 of the sleeve 1 applied to the cutting object 21, and the rotary blade body 4 is moved toward the axis line 1a of the sleeve 1 against the elastic force to allow a sliding contact between the inner circumferential surface 8 of the sleeve 1 and an outer circumferential surface 15 of the base end-side cutting section 10 of the cutter 7 which have been mutually set to identical diameters D8 and D15, when protruding the front end-side cutting section 9 and base end-side cutting section 10 of the cutter 7 outside the front-end opening 2 of the sleeve 1 applied to the cutting object 21.