A numerical controller which enables stroke limit check during a program check performed in a machine lock state and which can shorten the time required for the program check. The numerical controller has the function of checking a program while keeping a machine motion axis as a controlled object in an immovable state, and includes motion amount calculating means for analyzing the program to calculate an amount of movement of the machine motion axis, and updater means for updating machine coordinates by the motion amount of the machine motion axis calculated by the motion amount calculating means and storing the updated machine coordinates, wherein a motion area is checked based on the stored machine coordinates. Thus, even in the machine lock state, the machine coordinates are calculated, thereby permitting the stroke limit check to be performed during the program check.