A plasma generator that detects whether a connector of a head is electrically connected to a power cable. The plasma generator includes the head including the connector with a terminal to supply electricity to electrodes that generate plasma by electrical discharge, and a first terminal and a second terminal that are connected to each other; a power cable to supply electricity to the terminal; a cable to transmit a signal to the first terminal; a first ground cable to ground the second terminal; and a detector to detect a signal current that flows in a path from the cable to the first ground cable in accordance with transmission of the signal.