A numerical control apparatus for controlling a multiple-axis and multiple-channel machine tool by controlling multiple axes through multiple channels. A main processor (1) for executing data processings other than servo system processing, and an operator interface module (2), etc. are connected to a first bus (7). A plurality of servo command generating processors (10, 20, 30) for processing input data and producing a servo command for each channel are connected to the first bus (7) and a second bus (41). The second bus (41), which is connected to a plurality of servo control processors (42-45), transfers only servo command data and the first bus (7) transfers all other data. Accordingly, servo commands can be produced at a high speed, and thus a high-speed control of a multiple-axis and multiple-channel machine tool can be effected.