Detection device and storage medium storing a program

A detection device includes an idling feed threshold acquiring unit configured to acquire, as an idling feed threshold, a threshold of an acceptable load in an idling feed operation; an expected load acquiring unit configured to acquire, as an expected load, an expected increase in load due to execution of an actual machining operation; a calculating unit configured to calculate, based on the idling feed threshold and the expected load, an actual machining threshold which is a threshold of an acceptable load in the actual machining operation; an actual machining load acquiring unit configured to acquire, as an actual machining load, an actual load during an actual machining operation; and a detecting unit configured to detect, based on the operating mode, an excess of the actual machining load relative to the idling feed threshold or the actual machining threshold.