PURPOSE: To do drying and setting most suitable for hair and to prevent the over- drying of the hair, by a method wherein the moisture rate of the hair is determined covering a wide range while the hair is being brushed, and a hair-drying process is classified in three large regions, corresponding to the moisture rate.

CONSTITUTION: A detecting circuit N1 is provided in a bristle 2, detects a moisture rate through a moisture sensor 4, and consists of the moisture sensor 4, a transmitter 10, a transducing circuit 11 and an offset-compensating circuit 14. The detecting circuit 11 is a type of detecting an electrostatic capacity. A deciding means N5 consists of a first decision part N2 at which a signal is outputted when the output of the detecting circuit N1 is at a first level established as the criterion of the moisture rate, or higher; a second decision part N3 at which another signal is outputted when the output of the detecting circuit N1 is at a second level lower than the first level, or higher; and a third decision part N4 at which another signal is outputted when the output of the detecting circuit N1 is at a third level, or higher. In this way, when the moisture rate is at the first level or higher, a first notice is done, and when drying is advanced, a second notice is done, and thus a user is informed that the hair will be dried off in a short time and it is necessary to do hair-setting.