The following quote was obtained by the news editors from the background informa tion supplied bythe inventors: ““The present disclosure relates to a connector insertion method and an inspectio n method.“JP-A-2021-012784 discloses a robot apparatus for performing a step of gripping a first connector usinga robot and inserting the first connector into a second connector, a step of resonating the first connectorand the second connector in a state where the first connector is inserted into the second connector, and as tep of adjusting the insertion depth of the first connector based on resonance f requencies.