A bidirectional blower may include a blower body having a scroll rib making a length of an entire perimeter scroll guiding air flow in an internal space to an outlet end portion where air discharge is performed, and a fan in which a blade having an inlet angle of an acute angle and an outlet angle of an obtuse angle draws external air into the internal air, thereby realizing the characteristics of lowering an operating noise by preventing a generation of vortex while enhancing air volume performance suitable for a ventilation seat.