A centrifugal blower includes a rotation shaft, an impeller, a casing, and a deflection portion. The impeller rotates about the rotation shaft to draw an air therein in an axial direction of the rotation shaft and discharge the air outward in a radial direction of the rotation shaft. The impeller includes a plurality of blades and a side panel having an annular shape and connecting the plurality of blades in the axial direction. The casing accommodates the impeller and includes an air intake portion adjacent to the side panel. The air intake portion has a bell mouth shape to have a rim portion that defines an opening through which the drawn air is guided to an inside of the impeller. The deflection portion deflects an airflow along the rim portion of the air intake portion toward the side panel.