A noise control apparatus comprising: one or more reference sensors configured to detect a noise signal produced by a noise source; one or more sound emitting sources configured to emit a noise reduction signal and an identification signal; an error sensor configured to detect an acoustic signal component; identification means configured to carry out an identification operation of identifying an acoustic property in a noise reduction region based on the identification signal detected by the error sensor; and noise reduction signal generating means configured to generate the noise reduction signal by adaptive signal processing based on the detection by at least one of the reference sensors and the detection by the error sensor, wherein the identification means is configured to carry out the identification operation to acquire a change in the acoustic property in the noise reduction region based on a comparison between a frequency characteristic of a signal detected by the error sensor while at least one of the sound emitting sources emits the identification signal and do not emit the noise reduction signal and a frequency characteristic of a signal detected by the error sensor while at least one of the sound emitting sources emits a superimposed signal of the noise reduction signal and the identification signal, wherein the noise reduction signal generating means is configured to generate the noise reduction signal further based on the change in the acoustic property in the noise reduction region wherein the identification signal is an impulse signal, and characterized in that: the identification means is configured such that an operation period of the identification operation is between one minute and five minutes inclusive, and in the identification operation, the sound emitting source is configured to emit the impulse signal for an emission period of 0.5 seconds or less and repeat emitting at intervals of 3 seconds. one or more reference sensors configured to detect a noise signal produced by a noise source; one or more sound emitting sources configured to emit a noise reduction signal and an identification signal; an error sensor configured to detect an acoustic signal component; identification means configured to carry out an identification operation of identifying an acoustic property in a noise reduction region based on the identification signal detected by the error sensor; and noise reduction signal generating means configured to generate the noise reduction signal by adaptive signal processing based on the detection by at least one of the reference sensors and the detection by the error sensor, wherein the identification means is configured to carry out the identification operation to acquire a change in the acoustic property in the noise reduction region based on a comparison between a frequency characteristic of a signal detected by the error sensor while at least one of the sound emitting sources emits the identification signal and do not emit the noise reduction signal and a frequency characteristic of a signal detected by the error sensor while at least one of the sound emitting sources emits a superimposed signal of the noise reduction signal and the identification signal, wherein the noise reduction signal generating means is configured to generate the noise reduction signal further based on the change in the acoustic property in the noise reduction region wherein the identification signal is an impulse signal, and characterized in that: the identification means is configured such that an operation period of the identification operation is between one minute and five minutes inclusive, and in the identification operation, the sound emitting source is configured to emit the impulse signal for an emission period of 0.5 seconds or less and repeat emitting at intervals of 3 seconds. the identification means is configured such that an operation period of the identification operation is between one minute and five minutes inclusive, and in the identification operation, the sound emitting source is configured to emit the impulse signal for an emission period of 0.5 seconds or less and repeat emitting at intervals of 3 seconds.