An electromagnetic wave visualization device includes an image acquisition unit that captures an image of a target device, a measurement unit that measures an electromagnetic wave intensity of the target device, a controller that sets a measurement range of the measurement unit and generates a composite image in which a measurement result of the measured electromagnetic wave intensity is superimposed on the captured image of the target device acquired by the image acquisition unit, and an output unit that outputs the composite image generated by the controller, in which the controller generates the composite image including the measurement range of the measurement unit and outputs the composite image to the output unit.