A gas line (120) for supplying hydrogen gas and a harness (110) for supplying power to an electromagnetic valve are connected to an electromagnetic valve mechanism (200). The length of the harness (110) from a connecting member (111) to a fastener (160) is denoted by the letter “n” and the length of the gas line (120) from a connecting member (121) to a fastener (170) is denoted by the letter “m” (n