PURPOSE: To improve the operability of a lint filter and prevent the occurrence of a serious accident due to an erroneous operation to forget its fitting by covering it with a door for the access of the clothing into a drum, and providing the detecting function on whether the lint filter is normally installed or not.

CONSTITUTION: If a door switch 19 is set so that it is closed when a door 2 is closed, no operation is allowed when the door 2 is not closed surely, i.e., when a lint filter 14 is not installed at the normal position, and the occurrence of the leakage of lint into a circulating path can be prevented. A filter switch 18 is set so that it is closed when the lint filter 14 is installed, and the operation while the lint filter 14 is left removed can surely be prevented.