In a four-way valve having a simple structure, even if a high-temperature refrigerant and a low-temperature refrigerant flow close to each other, heat loss between both refrigerants is suppressed. The valve comprises a housing member including a valve chamber, a valve seat including a bearing surface portion located in the valve chamber, a first channel through which a high-temperature fluid flows and a second channel through which a low-temperature fluid flows at a predetermined time, including openings adjacent to each other at a bearing surface portion of the valve seat, passing through the valve seat and extending outside of the valve chamber, and a valve element moving to the bearing surface portion of the valve seat. A thermal resistor portion suppressing heat transfer between these channels is located near the openings, between the first and second channels.