To solve such problems that all operations for delivering drain in an automatic drain delivering device are stopped when a unified drain delivery device of a control side as a main apparatus is broken since a central control system is applied, it is difficult to subsequently increase the number of the device for generating drain capable of connecting to the unified drain delivery device of a control side as the main apparatus since the number is decided by the unified drain delivery device as the main apparatus which is disposed firstly, and it is complex since plural connection is necessitated even in the case of connection of a control circuit, and even in the case of connection of a drain delivery pipe.

In this drain delivering method for delivering the drain generated by compressed air at plural positions, all timings for turning on power supply used when the drain is delivered at the plural positions are equalized, delivering for the drain is independently controlled at the plural positions, and the drain is delivered at the plural positions so as to prevent the delivering from setting up in the same timings at two positions at least.