Numerical controller

A numerical controller for controlling a machine tool that has axes by executing a machining program that is made up of a plurality of blocks and controls acceleration/deceleration of the axes, the numerical controller comprising:

• a program execution unit that executes the machining program;
• a program look-ahead unit that looks ahead at the machining program in parallel with execution of the machining program;
• a look-ahead blocks calculation unit that calculates a look-ahead blocks, which is the difference between a first sequence number that is the number of a block being executed by the program execution unit and a second sequence number that is the number of a block that is looked ahead by the program look-ahead unit while the machining program is being executed;
• a required look-ahead blocks setting unit that sets a required look-ahead blocks, which is the look-ahead blocks required to execute the machining program;
• and
• an operation limitation unit that compares the look-ahead blocks calculated by the look-ahead blocks calculation unit and the required look-ahead blocks and, if the look-ahead blocks is less than the required look-ahead blocks, limits execution of the machining program by the program execution unit until the look-ahead blocks reaches the required look-ahead blocks.