An impeller of a centrifugal compressor, the impeller comprising: a plurality of full blades provided on a hub surface from a working fluid inlet part of the impeller to a fluid outlet part of the impeller; and a plurality of splitter blades, each splitter blade being provided between the full blade and the adjacent full blade from a middle of a flow passage formed between the full blades to the fluid outlet part of the impeller, wherein a leading edge blade angle (Θ) of a flow entering front-end-part of the splitter blade, which is the angle formed by the axial direction regarding the impeller and the blade slope direction regarding the splitter blade at the leading edge thereof, and which is set so that the direction of the leading edge blade angle (Θ) corresponds to the angles (Θ) of the slopes of the full blades at the leading edge location of the splitter blade, is varied depending on a height level from the hub surface in a height direction, wherein a hub side part of the flow entering front-end-part of the splitter blade is inclined smoothly toward a blade pressure surface side of the full blade, at a greater inclination angle than an inclination angle of other part of the flow entering front-end-part, the present impeller being characterised in that in an area where a span is shorter than or equal to approximately 70% of the total span, the leading edge blade angle (Θ) of the splitter blade is established so that a point is set to a point on a curve, wherein a variable of the leading edge blade angle (Θ) and a minus angle increment (-Δθ) thereof are a function of the height level (h), and wherein the minus angle increment (-Δθ) is 0 when the height level (h) is nearly equal to 70%, the minus angle increment (Δθ) is gradually increased while the height level (h) is decreased down to 0%; and, when the height level (h) reaches 0%, the increment (Δθ) is set as greater than or equal to approximately 15 degrees. a plurality of full blades provided on a hub surface from a working fluid inlet part of the impeller to a fluid outlet part of the impeller; and a plurality of splitter blades, each splitter blade being provided between the full blade and the adjacent full blade from a middle of a flow passage formed between the full blades to the fluid outlet part of the impeller, wherein a leading edge blade angle (Θ) of a flow entering front-end-part of the splitter blade, which is the angle formed by the axial direction regarding the impeller and the blade slope direction regarding the splitter blade at the leading edge thereof, and which is set so that the direction of the leading edge blade angle (Θ) corresponds to the angles (Θ) of the slopes of the full blades at the leading edge location of the splitter blade, is varied depending on a height level from the hub surface in a height direction, wherein a hub side part of the flow entering front-end-part of the splitter blade is inclined smoothly toward a blade pressure surface side of the full blade, at a greater inclination angle than an inclination angle of other part of the flow entering front-end-part, the present impeller being characterised in that in an area where a span is shorter than or equal to approximately 70% of the total span, the leading edge blade angle (Θ) of the splitter blade is established so that a point is set to a point on a curve, wherein a variable of the leading edge blade angle (Θ) and a minus angle increment (-Δθ) thereof are a function of the height level (h), and wherein the minus angle increment (-Δθ) is 0 when the height level (h) is nearly equal to 70%, the minus angle increment (Δθ) is gradually increased while the height level (h) is decreased down to 0%; and, when the height level (h) reaches 0%, the increment (Δθ) is set as greater than or equal to approximately 15 degrees.