Relay unit and producing method thereof

A relay unit electrically opens and closes between a battery (3) and a motor (4). Particularly, a third relay (50) connected in parallel with a precharge relay (30) that is of a first relay (30) and a second relay (40) is accommodated in a housing including a case (10) and a cover (70). The precharge relay (30) connects the battery (3) and the motor (4) and is connected in series with the precharge resistor (20).