A blower fan having a fan blade increasing air flow is provided to improve the performance of the blower fan by reducing noise through an air passage formed in an operation direction of the blower fan from the bottom surface of a fan blade. A blower fan comprises a plurality of fan blades(11) installed on the circumference. The top portion of the fan blade has a width different from that of a bottom portion thereof so that the amount of flowing medium introduced into the blower fan is increased or the introduced air is easily discharged. A passage guide is formed in the fan blade so that the top portion of the fan blade has the same width as that of the bottom portion thereof. An air passage is formed in an operation direction of the blower fan from the bottom surface of the fan blade to reduce operating noise of the fan blade.
