Centrifugal blower and air conditioning device

A centrifugal blower is provided with: an impeller including a rotationally driven main plate, an annular side plate, and a plurality of blades arranged on the circumferential edge of the main plate with one end thereof connected with the main plate and the other end connected with the side plate; and a scroll casing for accommodating the impeller, said scroll casing including a circumferential wall formed in a spiral shape and a side wall having a bell mouth which forms a suction port. The bell mouth includes a bell mouth circumferential wall formed protruding from the side wall in a cylindrical shape and an air intake section that is formed in an annular shape, in which the outer circumferential edge is connected with the end of the bell mouth circumferential wall in the direction of protrusion thereof, and in which the inner circumferential edge forms the suction port and has an opening diameter which gradually decreases toward the interior of the scroll casing. The scroll casing includes a barrier section