Abstract: Device suitable for detecting, evaluating and indicating noise levels, in the form of acoustic pressure, present in a place of work or others, e.g. places of entertainment. The device is suitable for recording the levels themselves, for a long period of time, with the possibility of comparison with reference levels which have been defined either from regulations in force, or from interpersonal or business agreements. The result of the comparison is indicated with continuity at many points, particularly signifying the situation in the room, to define the state of normality, of alarm or of danger, with many optical indicators of the traffic light type, which with the lighting of the green, amber or red lights, signify the current level of acoustic pressure. At the same time, the electronic registration of the data is highlighted on a monitor, with a corresponding graph, to suggest the possible need for intervention to a control operator.