Display system of working machine and display method of working machine

A display method of a working machine, the working machine comprising:

• one or a plurality of cameras that acquires a peripheral state of the working machine;
• and
• a monitor that displays predetermined information,
• the method comprising:
• a display control step of generating a temporally changing image and outputting, as a video signal, an image obtained by performing predetermined process on an image or images captured by the one or the plurality of cameras;
• a step of displaying, on the basis of the video signal output in the display control step, the temporally changing image and the image obtained by performing the predetermined process;
• and
• an abnormality determination step of determining that an abnormality has occurred in a case where the temporally changing image remains unchanged for a predetermined time.