PURPOSE: To shorten the time required for a drying operation and to reduce electric power consumption by detecting the humidity of a bath room and changing the ventilation rate of a ventilation means for discharge at a high rate when the detected humidity is higher than set humidity and at a low rate when the detected humidity is lower than the set humidity.

CONSTITUTION: This bath room drying machine is provided with a circulating fan 5 which sucks the air in the bath room into a casing 1 and passes the sucked air from a blow-off port 1b into the bath room, a discharge fan 6 which passes the air in the bath room to the outside of the bath room and a heat exchanger 7 which heats the circulating air and circulates the hot water from a heat source machine within a circulating path 10. The temp. and humidity in the bath room are detected by a temp. sensor St and a humidity sensor Sh at the time of drying in the bath room. The ventilation rate of the discharge fan 6 is so controlled in a controller C as to be set high at the time of the detected humidity > set humidity and to be low at the time of the detected humidity < set humidity or the ventilation rate of the circulating fan 5 to be set high at the time of the detected temp. < set temp. and to be low at the time of the detected temp. > set temp.