Material testing machine and method of controlling material testing machine

A method of controlling a material testing machine comprising:

• a load mechanism that applies a load to a test object;
• a load measurement device that measures the load applied to the test object;
• and
• a control device that perform is a feedback control for the load mechanism based on a deviation between a measurement value of the load and a target value of the load,
• the material testing machine measuring a change in a physical quantity generated in the test object due to the load,
• the method comprising causing the control device to detect hunting by comparing a frequency spectrum obtained by converting time-series data of the measurement value with a frequency spectrum obtained by converting time-series data of the target value, or by comparing a frequency spectrum obtained by converting time-series data of a command value of the feedback control with the frequency spectrum obtained by converting the time-series data of the target value.