An acoustic device comprising: a microphone; a voice feature amount extracting portion that is configured to extract a voice feature amount from a first audio signal representing sound collected by the microphone; a noise feature amount extracting portion that is configured to extract a noise feature amount including a noise level from the first audio signal; an audio signal receiving portion that is configured to receive a second audio signal from a different device on a far-end side; a gain determining portion that is configured to determine a gain of the second audio signal based on the extracted voice feature amount and the extracted noise feature amount, wherein the gain determining portion is configured to set the gain higher as the extracted voice feature amount is higher, wherein the gain determining portion is configured to set the gain lower as the extracted voice feature amount is lower, wherein the gain determining portion is configured to set the gain higher as the extracted noise feature amount is higher, wherein the gain determining portion is configured to set the gain lower as the extracted noise feature amount is lower, wherein the gain determining portion is configured to set the gain limited to values equal to or lower than one, and wherein the gain determining portion is configured to set the gain linearly proportional to the voice feature amount; and a gain adjusting portion that is configured to adjust the second audio signal based on the determined gain of the second audio signal, wherein the noise feature amount extracting portion is configured to calculate a power of the first audio signal as the noise feature amount in a case that the power of the first audio signal is less than or equal to a predetermined value, and a power of the second audio signal received by the audio signal receiving portion is less than a predetermined threshold value. a microphone; a voice feature amount extracting portion that is configured to extract a voice feature amount from a first audio signal representing sound collected by the microphone; a noise feature amount extracting portion that is configured to extract a noise feature amount including a noise level from the first audio signal; an audio signal receiving portion that is configured to receive a second audio signal from a different device on a far-end side; a gain determining portion that is configured to determine a gain of the second audio signal based on the extracted voice feature amount and the extracted noise feature amount, wherein the gain determining portion is configured to set the gain higher as the extracted voice feature amount is higher, wherein the gain determining portion is configured to set the gain lower as the extracted voice feature amount is lower, wherein the gain determining portion is configured to set the gain higher as the extracted noise feature amount is higher, wherein the gain determining portion is configured to set the gain lower as the extracted noise feature amount is lower, wherein the gain determining portion is configured to set the gain limited to values equal to or lower than one, and wherein the gain determining portion is configured to set the gain linearly proportional to the voice feature amount; and a gain adjusting portion that is configured to adjust the second audio signal based on the determined gain of the second audio signal, wherein the noise feature amount extracting portion is configured to calculate a power of the first audio signal as the noise feature amount in a case that the power of the first audio signal is less than or equal to a predetermined value, and a power of the second audio signal received by the audio signal receiving portion is less than a predetermined threshold value. the power of the first audio signal is less than or equal to a predetermined value, and a power of the second audio signal received by the audio signal receiving portion is less than a predetermined threshold value.