Abstract: An impeller for use in a centrifugal blower comprises a hub for receiving a driving torque at a central portion thereof, a shroud of a ring-like shape in plane formed with an opening for air intake at the center thereof and opposed to the hub across a required distance therebetween, and a plurality of vane members interposed between the hub and shroud as circumferentially spaced from one another at required intervals, the impeller having an arrangement wherein an leading edge of each vane member has varied angles (inlet angles) with respect to a tangent line thereat thereby conforming to inflow angles of an air flow guided by the vane member at different points of a span between the shroud and hub.