To provide a hole drilling tool, and a hole drilling method advantageous to highly efficient work, restraining deviation and deflection of the axis of the hole drilling tool, and restraining a risk of damaging a work surface of a hole of a work when pulling out the hole drilling tool from the hole of the work after finishing hole drilling.

This hole drilling tool 1 has a shaft-like part having the axis P, and a blade group 14 arranged in the shaft-like part, and composed of at least three blades 11, 12, and 13 juxtaposed at an interval in the peripheral direction with the axis P as the center. Among the blades 11, 12, and 13 for constituting the blade group 14, at least two blades are arranged so that distances from the axis P are varied, and the cutting functions are varied, and are retractably set. Here, the first blade 11, the second blade 12, and the third blade 13 are desirably varied in their cutting functions.