A scroll shape of a compressor forms into a spiral shape a flow path of fluid discharged from a diffuser provided on a downstream side of the compressor in a fluid flow direction. The scroll shape has a scroll outer diameter that is not constant in a circumferential direction. An increase degree of a ratio A/R is set to be increased in a range from a winding start position to a winding end position of a scroll portion where A is a passage cross-sectional area of the scroll portion and R is a radius from a center of the compressor to a center of a passage cross section of the scroll portion.