PURPOSE: To perform comfortable room heating without air flow staying sense by periodically controlling the direction of hot air flow.

CONSTITUTION: When a blower 4 is rotated, air flow is flowed from an inlet 5, and flowed out from an outlet 6. At this time heat from a heat source 2 is transmitted through a heat exchanger 3, and outflowing air becomes hot. A direction control vane 7 disposed in the outlet 6 is swung at the diffusing air flow by the rotation of a motor 10 in upward and downward directions. When the manual setter 13 of a fluctuating period signal setter 15 is set to the desired position, a period set signal is fed to a microcomputer 16, which calculates the period. The motor 10 is driven on the basis of the period, thereby performing comfortable swing by the hot air.