Abstract: This tool selection method is provided with: a step for respectively calculating, with respect to a plurality of known workpieces, feature amounts based on the shapes of a plurality of machining surfaces wherein, to each of the plurality of known workpieces, one main tool which is preselected from a tool list that includes a plurality of tools is allocated as being suitable for machining the plurality of machining surfaces; a step for executing, with respect to the plurality of known workpieces, machine learning by taking the feature amounts as inputs and the main tools as outputs; a step for calculating a feature amount for a target workpiece; and a step for selecting, with respect to the target workpiece, a main tool from the tool list on the basis of a machine learning result obtained by using the feature amount of the target workpiece as an input.