Centrifugal blower

A centrifugal blower 1 includes a scroll 2 that accommodates an impeller 5 having many blades 5a arranged in a circumferential direction around a rotating shaft 9. The centrifugal blower 1 sucks air from a suction port 3 and discharges the sucked air toward an outside of a discharge port 4 via each space of blades 5a. An enclosure 8 controls backward flow air discharged toward a vicinity of the discharge port 4. The enclosure 8 is disposed in a circumferential direction around the suction port 3 in the scroll 2. The enclosure 8 encloses an outside circumference of the impeller 5 at regular intervals.