PURPOSE: To supply each of a plurality of tea processing machines with hot air having characteristics which accord with the requirement of the machine, economically, without degrading the tea leaves, by introducing hot air generated from a heat exchanger connected with a boiler, through a flow-controlling valve and a cool-air blower to the machine.

CONSTITUTION: Each of the tea processing machines 1W4, e.g. coarse rolling machine, dryer, etc., is supplied with hot air from a heat exchanger 6 connected to a common boiler 5. The characteristics of the hot air are controlled by the flow- controlling valve 8W11 and a cool air blower 12W15 to meet the requirement of the machine. Since the hot air is separated from the combustion gas of the boiler by the heat exchanger 6, the degradation of the taste and flavor of tea leaves caused by the direct contact with the combustion gas, can be prevented. The total equipment cost can be reduced by using the single common boiler.