To provide the noise suppressing device in which no limitation is imposed on the environmental conditons when using the device in the environment to reduce the noise caused by the cooling fan that is provided within an electronic equipment.

A cooling fan 2 is provided in the electronic equipment for cooling purposes. In order to reduce cooling fan noise 5, a ventilation duct 3 is mounted on the cooling fan discharge port and a means is provided to electrically compensate for the vibration values of the fan 2 detected by a sensor 4. Moreover, the device is provided with an adaptive filter 10 which generates cancelling sounds 7, that are outputted by a speaker 6 and reduce the noise 5 by interference. Furthermore, a characteristics updating means of the filter 10 and a sound collecting means, which monitors the interference result of the noise 5 and the sounds 7, are provided.