A blower fan unit includes a housing, an impeller, an outlet, and a positioning mechanism. The impeller is mounted in the housing. The impeller rotates around a rotation center axis and generates an air current in a centrifugal direction from the rotation center axis. An outlet is formed in the housing and located in a centrifugal direction from the rotation center axis. A positioning mechanism is connected to the housing and makes the position of the housing change along the rotation center axis at each angular position around the rotation center axis.