An electromagnetic stylus includes a hollow body, a pen-nib device, an energy transforming device, a circuit board, and an electricity storage device. The pen-nib device is disposed at one end of the hollow body. The energy transforming device is disposed in the hollow body for converting variations in a physical quantity into electrical signals. The circuit board is disposed in the hollow body and electrically connected to the energy transforming device for rectifying the electrical signals transformed by the energy transforming device. The electricity storage device is disposed in the hollow body and electrically connected to the pen-nib device, for receiving the electrical signals transmitted from the circuit board to generate electrical energy and providing the electrical energy to the pen-nib device to generate electromagnetic signals.