A power supply system includes a wearing part worn on a hand of a worker, a connecting member held by the wearing part, and a control circuit. The connecting member is disposed at a position where it is attached to a tool-side attachment part provided on a grip of a power tool when the worker grips the grip. The connecting member includes, in an exposed manner, a power source terminal that supplies electric power to the power tool and a signal terminal that receives a response signal from the power tool, which are electrically connected to the power tool in an attached state where the connecting member is attached to the tool-side attachment part. The control circuit makes the power source terminal and a power source unit electrically continuous when the signal terminal receives the response signal and makes them electrically discontinuous when the signal terminal receives no response signal.