An insert tip used when steel or cast iron is worked, in which clearance portions are provided inside bolt holes formed in the insert tip to slantingly fit a bolt into the bolt holes, the bolt serving to fix the insert tip to a cutter body, so that more insert tips can be firmly fixed to the cutter body. To this end, in an insert tip including bolt holes that cause upper and lower surfaces of a plate shaped body to communicate with each other, the plate shaped body having a cutting edge at each corner portion, the insert tip being fixed to a cutter body by a bolt fitted into the bolt holes, clearance portions are formed at a portion direction toward each corner portion of the insert tip among inner side portions of the bolt holes to prevent interference between the bolt holes and the bolt if the bolt is slantingly fitted from one corner portion of the insert tip, where the insert tip is worked, to its opposite corner portion.