Patent ID: 8388279

Claim:
A drilling tool comprising: a substantially columnar tool body to be rotated around an axial line; a cutting edge located at a front end portion of the tool body; and a chip suction hole which is formed inside the tool body in a direction of the axial line for sucking chips generated by the cutting edge, wherein: the chip suction hole comprises: a main hole portion extending toward a tool base along the axial line; a narrow hole portion located at a front end of the main hole portion, the narrow hole portion having a cross section smaller than that of the main hole portion; and a suction opening located at a front end of the narrow hole portion and opened in the vicinity of the cutting edge, the suction opening having a cross section larger than that of the narrow hole portion, wherein: at least one groove is provided on an outer periphery of the tool body so as to permit outside air to be taken in during drilling.