PURPOSE: To perform management of a tool life by setting machining data and the life of a tool to a numbered tool file, grouping the tool files in a manner to be classified by a machining kind to form a tool group file, and containing the code of the tool group file in a machining program.

CONSTITUTION: After a machining program 13 is produced and stored in a memory 101, a TG screen 41 is displayed and a TD number of a tool needed classified by the TG number of a tool group file 12 is inputted to produce the tool group file 12. The tool group file 12 is stored in a TG data memory 102 by a group file storing means 4. A TG screen 42 is then displayed and machining data and a life set value are set at a TD number set by the tool group file 12 to produce a tool file 11, which is stored in a memory 103. A correction screen 44 is produced to produce a correction value file 14, which is stored in a memory 104. Based on data in the memories 101-104, execution type data is produced to perform machining.