Abstract: Disclosed is a pipe expanding punch for a drill, which is configured to expand a pipe by hitting the pipe by an anchor drill or a rechargeable drill. The pipe expanding punch includes: an expanding mandrel provided with at least one portion (hereinafter referred to as “an expanding part”) having an outer diameter larger than an inner diameter of a pipe to be expanded; and a holder formed integrally with the expanding mandrel and fixedly coupled to a drill such that the pipe is expanded using the drill, wherein the outer diameter of an introduction part of an end portion of the expanding mandrel is smaller than the inner diameter of the pipe, a first tapered step is provided between the introduction part and the expanding part, and at least one polished flat surface is formed by polishing the first tapered step.