A method for controlling a dryer including: a drum for holding drying objects, an air supply unit for supplying air to the drum, a duct for discharging the air from an inside of the drum, a filter assembly detachably mounted to the duct, the filter assembly having a filter portion for filtering the air being discharged from the drum, and a brush for removing foreign matter from the filter portion, a brush driving unit for making the brush to reciprocate a region of the filter portion, and position sensing means for sensing a position of the brush, - wherein the position sensing means includes magnetic force generating means provided to the brush and two magnetic force sensing means (510a, 510b) for sensing whether the magnetic force generating means reaches to limiting points of the reciprocating movement of the brush or not, the method comprises: - a mount sensing step for determining whether the filter assembly is mounted to the duct or not depending on whether the position sensing means senses a position of the brush or not after putting the brush driving unit into operation temporarily; - a pre-drying notifying step for requesting the user to inspect the filter assembly with a display unit or a speaker provided to the dryer if both of the two magnetic force sensing means (510a, 510b) can not sense the magnetic force generation means in the mount sensing step; - wherein the pre-drying notifying step includes the step of requesting the user to remove the foreign matter from the filter assembly without stopping operation of the dryer when only one of the two magnetic force sensing means (510a, 510b) senses the position of the magnetic force generating means, - wherein if both of the two magnetic force sensing means (510a, 510b) can not sense the position of the magnetic force generating means, the pre-drying notifying step progresses the step of requesting the user to remove the foreign matter from the filter assembly, and stopping operation of the dryer, - an air supply step for putting the air supply unit into operation to supply the air to the drum, and - a filter cleaning step for controlling the brush driving unit to make the brush to remove the foreign matter from the filter portion during the air supply step is in progress, - wherein the air supply step is progressed, if at least one of the two magnetic force sensing means (510a, 510b) senses a position of the magnetic force generating means. - wherein the position sensing means includes magnetic force generating means provided to the brush and two magnetic force sensing means (510a, 510b) for sensing whether the magnetic force generating means reaches to limiting points of the reciprocating movement of the brush or not, - a mount sensing step for determining whether the filter assembly is mounted to the duct or not depending on whether the position sensing means senses a position of the brush or not after putting the brush driving unit into operation temporarily; - a pre-drying notifying step for requesting the user to inspect the filter assembly with a display unit or a speaker provided to the dryer if both of the two magnetic force sensing means (510a, 510b) can not sense the magnetic force generation means in the mount sensing step; - wherein the pre-drying notifying step includes the step of requesting the user to remove the foreign matter from the filter assembly without stopping operation of the dryer when only one of the two magnetic force sensing means (510a, 510b) senses the position of the magnetic force generating means, - wherein if both of the two magnetic force sensing means (510a, 510b) can not sense the position of the magnetic force generating means, the pre-drying notifying step progresses the step of requesting the user to remove the foreign matter from the filter assembly, and stopping operation of the dryer, - an air supply step for putting the air supply unit into operation to supply the air to the drum, and - a filter cleaning step for controlling the brush driving unit to make the brush to remove the foreign matter from the filter portion during the air supply step is in progress, - wherein the air supply step is progressed, if at least one of the two magnetic force sensing means (510a, 510b) senses a position of the magnetic force generating means.