PURPOSE: To achieve high efficiency in machining of a honeycomb core by reducing the machining resistance, and preventing seizure of a cutter tip.

CONSTITUTION: In a honeycomb core machining tool equipped with a plurality of spiral cutter parts at the periphery, the cutter parts 3 are formed in single piece structure at the periphery of a columnar part 2 provided in continuity at the tip of the tool shank 1, wherein the lead angle (r) of each cutter part is made over m60deg., and the cutter part is provided with a circumferential cutter 4 having a cutting edge of tip angle α between 1-20deg. and a bottom cutter 5 formed in continuity to the circumferential cutter curving convex outward in the tool rotating direction, and having a cutting edge of tip angle βbetween 1-20deg.