PURPOSE: To give a warning when a sound being a noise to an adjacent room and vibration are generated.

CONSTITUTION: A device monitors a noise generated in a room of a multiple dwelling house. A vibrational acceleration sensor 10 is arranged on a floor of the room, and measures vibrational acceleration of the floor. A measuring device 14 finds a vibrational acceleration level with every octave band from an output signal of this sensor 10, and an exciting force calculating circuit 15 calculates exciting force applied to the floor on the basis of this vibrational acceleration level and vibrational acceleration admittance of the premeasured floor. An impact sound calculating circuit 17 calculates sound pressure in a lower room by using the calculated exciting force and the floor impact sound insulating grade L number of the floor, and a judging-warning circuit 20 makes a warning device 22 give a warning by a sound and the light when the calculated sound pressure exceeds a reference value. A sound pressure sensor 9 measures a sound of a stereo or the like, and a measuring device 11 and a transmitted sound calculating circuit 12 calculate a level of a transmitted sound to an adjacent room. The judging-warning circuit 20 gives a warning by its result.