From the Super Mario Wiki
The Clockwork Room (Japanese: からくり部屋 Mechanism Room) is a room found in Area Four of Luigi's Mansion. This is where Luigi fights the Clockwork Soldiers. After Luigi defeats them, he proceeds to the Roof.
The Clockwork Room is a large room with many items. There are three clocks Luigi can shake to activate. Four chairs, two on each side of the room, are present, as well as a marionette on either side. The Clockwork Soldiers themselves stand in front of three small houses, the middle of which opens to reveal an elevator to the Roof.