A blower, including: a volute including air inlets and an air outlet; a wind wheel disposed in the volute; and air collectors. Each air collector includes a curved air guide. The air inlets are disposed at two sides of the wind wheel, respectively. The air collectors correspond to the air inlets. The curved air guide extends into the volute, and the inner diameter of the curved air guide decreases stepwise. The relationship between a minimum inner diameter D0 of the curved air guide and an inner diameter D1, an outer diameter D2 of the wind wheel fulfills the following formula: D1+⅓(D2−D1)≤D0≤D1+⅔(D2−D1). An exhaust fan that includes the blower is also provided.