A sound collecting apparatus comprising: a plurality of microphones (20a, 20b, 20c, 20d) arranged on the same plane, a processor; and a non-transitory recording medium storing thereon a computer program, wherein among a plurality of microphone pairs each configured of any two microphones (20a, 20b, 20c, 20d) included in the plurality of microphones (20a, 20b, 20c, 20d), a total number of a plurality of effective microphone pairs in which a distance between the two microphones (20a, 20b, 20c, 20d) is smaller than a distance D is larger than a total number of the plurality of microphones (20a, 20b, 20c, 20d), the distance D is represented by D = c/2f, where the frequency of the target sound acquired from the plurality of microphones (20a, 20b, 20c, 20d) is f and a predetermined sound velocity is c, and when an angle formed by a straight line (L1, L2, L3, L4, L5, L6) connecting two microphones (20a, 20b, 20c, 20d) configuring each of the plurality of effective microphone pairs and a predetermined straight line within the plane is θ, the angles θ of all of the plurality of effective microphone pairs acquired from the plurality of microphones (20a, 20b, 20c, 20d) are different from each other, characterized in that the computer program, when executed by the processor, causes the processor to perform operations including giving a delay to a voice signal acquired from each of the plurality of microphones (20a, 20b, 20c, 20d) to generate delayed output signals, generating a first signal by adding the delayed output signals, generating a second signal by performing subtraction on output signals corresponding to each of the plurality of the effective microphone pairs among the delayed output signals, applying a filter coefficient to each of the second signals, generating an output signal by subtracting all the second signals applied with the filter coefficient from the generated first signal, and updating the filter coefficient based on the output signal,. a plurality of microphones (20a, 20b, 20c, 20d) arranged on the same plane, a processor; and a non-transitory recording medium storing thereon a computer program, wherein among a plurality of microphone pairs each configured of any two microphones (20a, 20b, 20c, 20d) included in the plurality of microphones (20a, 20b, 20c, 20d), a total number of a plurality of effective microphone pairs in which a distance between the two microphones (20a, 20b, 20c, 20d) is smaller than a distance D is larger than a total number of the plurality of microphones (20a, 20b, 20c, 20d), the distance D is represented by D = c/2f, where the frequency of the target sound acquired from the plurality of microphones (20a, 20b, 20c, 20d) is f and a predetermined sound velocity is c, and when an angle formed by a straight line (L1, L2, L3, L4, L5, L6) connecting two microphones (20a, 20b, 20c, 20d) configuring each of the plurality of effective microphone pairs and a predetermined straight line within the plane is θ, the angles θ of all of the plurality of effective microphone pairs acquired from the plurality of microphones (20a, 20b, 20c, 20d) are different from each other, characterized in that the computer program, when executed by the processor, causes the processor to perform operations including giving a delay to a voice signal acquired from each of the plurality of microphones (20a, 20b, 20c, 20d) to generate delayed output signals, generating a first signal by adding the delayed output signals, generating a second signal by performing subtraction on output signals corresponding to each of the plurality of the effective microphone pairs among the delayed output signals, applying a filter coefficient to each of the second signals, generating an output signal by subtracting all the second signals applied with the filter coefficient from the generated first signal, and updating the filter coefficient based on the output signal,. giving a delay to a voice signal acquired from each of the plurality of microphones (20a, 20b, 20c, 20d) to generate delayed output signals, generating a first signal by adding the delayed output signals, generating a second signal by performing subtraction on output signals corresponding to each of the plurality of the effective microphone pairs among the delayed output signals, applying a filter coefficient to each of the second signals, generating an output signal by subtracting all the second signals applied with the filter coefficient from the generated first signal, and updating the filter coefficient based on the output signal,.