A composite valve includes a valve body, a first valve module, and a second valve module. The valve body includes a first body portion to which the first valve module is attached, a second body portion to which the second valve module is attached, a third body portion that has an input port, and a fourth body portion that has an output port and an attachment portion. The first body portion and the second body portion respectively extend along a first axis and a second axis that are parallel to each other. The third body portion extends along a third axis that is at 90 degrees with respect to the first axis and with respect to the second axis. The fourth body portion extends along a fourth axis L4 that is at 90 degrees with respect to all the first axis, the second axis, and the third axis.