A control device includes a task execution unit; a storage unit which stores a variable in a program, which is capable of being referenced and updated; and a collection unit which collects a variable when a task is executed. The storage unit stores reference data corresponding to the variable. A plurality of tasks include: an update task which is capable of updating and referencing the variable; and a reference task which is capable of referencing the reference data. The collection unit collects the reference data when the plurality of tasks are executed.