A passage switching device to switch flow passages includes a rotary disk and a fixed disk which are stacked in an axial direction. The rotary disk is provided with at least one rotary disk communication path penetrating in the axial direction, and the fixed disk is provided with a plurality of fixed disk communication paths penetrating in the axial direction. The flow passages are switched by rotating and driving the rotary disk to switch combination of the rotary disk communication path and the fixed disk communication path for communication. There is provided an elastic member between the housing and the rotary disk, between the rotary disk and the fixed disk, and between the fixed disk and the housing with respect to the axial direction.