A hammer drill is provided with a connector equipped with a female terminal, movably between a connection position where the female terminal is located inside a plug-in port and a non-connection position where the female terminal is in retreat from inside the plug-in port. According to a second aspect of the invention, the recording sheet includes a paper substrate having a surface treatment including a water soluble cationic substance and a water soluble binder substance. The igniter, which starts a flame, connects to a first terminal which provides a power signal with respect to a neutral terminal.