A numerical controller determines whether or not block prefetching from a program is sufficient based on whether at least one block subsequent to a predetermined reference block, which exists after a running block of the program and is needed to execute the reference block, has been prefetched or not. If the determination result is that prefetching is not sufficient, block prefetching from the program is performed.

A numerical controller determines whether or not block prefetching from a program is sufficient based on whether at least one block subsequent to a predetermined reference block, which exists after a running block of the program and is needed to execute the reference block, has been prefetched or not. If the determination result is that prefetching is not sufficient, block prefetching from the program is performed.

Disclosed is a numerical controller that recognizes a range between a machining command for a tool number previously designated by an NC program for machining control and a machining command for the next tool number as a single machining process, generates a machining cycle command from the recognized single machining process, and generates an NC program in which the single machining process on the NC program is replaced by the generated machining cycle command.