A bladed wheel of a blower device has a main plate, a side plate and multiple fan blades between the main plate and the side plate. A fan casing of the blower device has a bell mouth portion and a guide wall portion, which extends in a radial-outward direction from an axial rear-side end of the bell mouth portion to an outer periphery of the side plate. An air reflecting space is formed in the fan casing at a radial-outside position of the guide wall portion and at an axial front-side position of the fan casing between an axial rear-side end of the guide wall portion and an axial front-end wall portion of the fan casing. Air blown out from the bladed wheel flows through an air blow-out passage, wherein sound wave of the air from the bladed wheel and sound wave of the air from the air reflecting space interfere with each other so that noise is decreased.