A recirculation valve configured to open or close a recirculation line connected to a front stage of a compressor from a rear stage of the compressor on an intake line of an engine is provided. The valve includes a recirculation valve adaptor that has an inlet into which gas is introduced formed in a bottom thereof, having an outlet from which the gas is discharged formed in a first side of a side surface thereof, and having an inner space connected to the inlet and the outlet and in which the gas flows. A plug is configured to open or close the inlet and the outlet. The inner space has an asymmetric shape in which a width in a horizontal direction is increased in a direction from the other side of an inside surface to one side thereof.