Abstract: A numerical control device that suspends tasks related to a machining process when designated conditions are satisfied to execute a designated program as an interrupt. A numerical control device includes: a task management unit that manages tasks that execute a machining program and tasks executed on the background of the tasks that execute the machining program; an interrupt notification unit that monitors system data set to an interrupt condition designated in advance and outputs an interrupt command upon detecting that the interrupt condition is satisfied; and an interrupt processing unit that suspends the tasks being executed at a time point when the interrupt command was received to execute a predetermined interrupt program as an interrupt on the basis of the interrupt command output by the interrupt notification unit.