Abstract: An array microphone is a directional microphone having an improved directional characteric in which both the sensitivity and the sound pressure frequency response are uniform within the recording area and more particularly, the quality and level of sound remain unchanged. The array microphone includes a microphone array including a plurality of microphone units, and a two-dimensional filter for filtering an output of the microphone array in the dimensions of both time and space. When the two-dimensional filter is a digital filter and varied in its two-dimensional filter coefficient and sampling frequency, the array microphone serves as a variable directional microphone whose directional characteristic can be varied with the sound quality and level remaining unchanged throughout the recording area.