A valve device comprises a case comprising an open lower portion and an accommodation space formed therein, a base plate to cover the open lower portion of the case, an inlet pipe connected to the base plate and through which a refrigerant is introduced to the accommodation space, a boss installed to the base plate and comprising a plurality of refrigerant inlet and outlet holes through which the introduced refrigerant from the accommodation space is introduced and discharged, a plurality of inlet and outlet pipes respectively connected to the plurality of refrigerant inlet and outlet holes, and through which the refrigerant is introduced from the boss or discharged to the boss, and a pad comprising an open cavity formed therein to selectively open one refrigerant inlet and outlet hole, and a connection cavity formed therein to selectively connect two refrigerant inlet and outlet holes.