A plurality of electrical connection structures are provided. Each of the electrical connection structures includes a plurality of electrical wires each having a wiring portion and an electrical connection portion directly or indirectly electrically connected to an electromagnetic valve (a control unit) at an end of the wiring portion, and wiring plates on which wiring portions are arranged. Between the electrical connection structures disposed next to each other, another end of the wiring portion of the electrical connection structure establishes an electrical connection relation with the another end of the wiring portion of the electrical connection structure. Between the electrical connection structures disposed next to each other, a movable portion capable of changing a relative positional relation therebetween is provided.