PURPOSE: To enable a numerial control machine to inform, by itself, the data of maintenance such, as for example, a time of inspection of machines, etc., by providing such an arrangement that the incoming of the time is worned and displayed with the use of timers which are set in accordance with the maintenance time, etc.

CONSTITUTION: The periodical inspection time of a numerical inspection machine is set on a timer T1, the times of replacement or maintenance of specific component parts are set on timers T2, T3, and the periodical maintenance and overhaul times of machines are set on timers H1, H2. After energization, timers T1 through T3 count up at every fixed time period, and a CPU1 allows the timer H1, H2 to count up at every fixed time period after it issuses a driving instruction to an object to be controlled through an input circuit 5. With this arrangement, the timers T1 through T3 count up during operation of the numerical control device while the timers H1, H2 counts up during the machines to be controlled are driven. Meanwhile, the CPU1 issues a signal through the circuit 5 when the timers T1 through T3, H1, H2 reach their set values to warn such that lamps are flushed, and the screen of a display device 6 to be observed is changed over, and so forth.