A numerical controller capable of temporarily executing dedicated function software includes a dedicated function software reading unit configured to read, in response to a reading condition being satisfied, the dedicated function software into a primary storage area mainly accessed by a CPU, dedicated function software execution unit configured to execute the dedicated function software as a process in response to an execution condition being satisfied, and a dedicated function software termination unit configured to stop execution of the process of the dedicated function software and delete the dedicated function software from the primary storage area in response to a termination condition being satisfied.