A numerical controller is configured to be able to automatically extract a machining program of a deletion candidate and includes: a storage period designating unit that sets a storage period of a machining program; a use date recording unit that records a date on which the machining program is used; a deletion candidate selecting unit that extracts the machining program of the deletion candidate based on the storage period and the use date; and a deleting unit that deletes the machining program of the deletion candidate.