A load testing apparatus comprising: a resistor unit that has a resistor group (G1-G4) including relays and resistors (R1 - R6) and is connected to a power source to be tested to perform a load test; a selection switch that is used to select whether to supply power from the power source to be tested to the resistor group (G1 - G4); an electrical signal detection unit that detects at least one of a voltage applied to the resistor unit and a current flowing through the resistor unit; and a control unit, wherein the relay is configured to operate in response to an on/off state of the selection switch to control power supply from the power source to be tested to the resistor group (G1 - G4) including the relay, the control unit is configured to perform determination on whether the relay normally operates based on detection information including a time-series change of at least one of the voltage and the current when the selection switch is operated, which is information from the electrical signal detection unit, and is further configured to perform off control to stop power supply from the power source to be tested to the resistor unit when it is determined that the relay does not normally operate, the control unit is configured to perform a comparison between reference information and the detection information, and performs the determination based on a result of the comparison, the reference information is information of the time-series change of at least one of the voltage and the current when the selection switch is operated, and is recorded in advance before performing the load test, a reference waveform region as the reference information, which includes a waveform representing the time-series change of at least one of the voltage and the current when the selection switch is operated and is represented in a curve having a constant width, is compared with the detection information, and the control unit is further configured to perform the determination based on a length of a time zone of a waveform representing the detection information that is included in the reference waveform region when the waveform representing the detection information is superimposed on the reference waveform region. a resistor unit that has a resistor group (G1-G4) including relays and resistors (R1 - R6) and is connected to a power source to be tested to perform a load test; a selection switch that is used to select whether to supply power from the power source to be tested to the resistor group (G1 - G4); an electrical signal detection unit that detects at least one of a voltage applied to the resistor unit and a current flowing through the resistor unit; and a control unit, wherein the relay is configured to operate in response to an on/off state of the selection switch to control power supply from the power source to be tested to the resistor group (G1 - G4) including the relay, the control unit is configured to perform determination on whether the relay normally operates based on detection information including a time-series change of at least one of the voltage and the current when the selection switch is operated, which is information from the electrical signal detection unit, and is further configured to perform off control to stop power supply from the power source to be tested to the resistor unit when it is determined that the relay does not normally operate, the control unit is configured to perform a comparison between reference information and the detection information, and performs the determination based on a result of the comparison, the reference information is information of the time-series change of at least one of the voltage and the current when the selection switch is operated, and is recorded in advance before performing the load test, a reference waveform region as the reference information, which includes a waveform representing the time-series change of at least one of the voltage and the current when the selection switch is operated and is represented in a curve having a constant width, is compared with the detection information, and the control unit is further configured to perform the determination based on a length of a time zone of a waveform representing the detection information that is included in the reference waveform region when the waveform representing the detection information is superimposed on the reference waveform region.