A material testing machine comprising: a load mechanism configured to apply a test force to a test piece; a detector comprising a physical quantity detection mechanism configured to measure a physical quantity when the test force is given to the test piece by the load mechanism; a control device; a cable configured to connect the detector with the control device; and a display part configured to display a measurement result of the detector,_ characterized in that: the control device is configured to output an AC carrier wave signal for exciting the physical quantity detection mechanism via the cable, and_wherein the control device includes: a detection circuit which is configured to receive a modulated AC carrier wave as a measurement signal input from the physical quantity detection mechanism via the cable wherein the detection circuit is configured to extract from the received signal a resistance component caused by the physical quantity and a capacitive component caused by an electrostatic capacitance of the cable from a measurement signal from the physical quantity detection mechanism, a memory element which is configured to store a normal capacitive component extracted by the detection circuit, and a comparator which is configured to compare a current capacitive component extracted by the detection circuit with the normal capacitive component, and wherein the control device is configured to, when a comparison result from the comparator indicates that a value of the current capacitive component varies beyond a predetermined allowable range with respect to the normal capacitive component, treat that the cable is disconnected, and provide a disconnection warning. a load mechanism configured to apply a test force to a test piece; a detector comprising a physical quantity detection mechanism configured to measure a physical quantity when the test force is given to the test piece by the load mechanism; a control device; a cable configured to connect the detector with the control device; and a display part configured to display a measurement result of the detector,_ characterized in that: the control device is configured to output an AC carrier wave signal for exciting the physical quantity detection mechanism via the cable, and_wherein the control device includes: a detection circuit which is configured to receive a modulated AC carrier wave as a measurement signal input from the physical quantity detection mechanism via the cable wherein the detection circuit is configured to extract from the received signal a resistance component caused by the physical quantity and a capacitive component caused by an electrostatic capacitance of the cable from a measurement signal from the physical quantity detection mechanism, a memory element which is configured to store a normal capacitive component extracted by the detection circuit, and a comparator which is configured to compare a current capacitive component extracted by the detection circuit with the normal capacitive component, and wherein the control device is configured to, when a comparison result from the comparator indicates that a value of the current capacitive component varies beyond a predetermined allowable range with respect to the normal capacitive component, treat that the cable is disconnected, and provide a disconnection warning. a detection circuit which is configured to receive a modulated AC carrier wave as a measurement signal input from the physical quantity detection mechanism via the cable wherein the detection circuit is configured to extract from the received signal a resistance component caused by the physical quantity and a capacitive component caused by an electrostatic capacitance of the cable from a measurement signal from the physical quantity detection mechanism, a memory element which is configured to store a normal capacitive component extracted by the detection circuit, and a comparator which is configured to compare a current capacitive component extracted by the detection circuit with the normal capacitive component, and wherein the control device is configured to, when a comparison result from the comparator indicates that a value of the current capacitive component varies beyond a predetermined allowable range with respect to the normal capacitive component, treat that the cable is disconnected, and provide a disconnection warning.