1. An acoustic measurement device comprising: a sound reception section that includes a plurality of unidirectional microphones that are configured to produce measurement values, the plurality of the unidirectional microphones being arranged such that a total sum of unit vectors of the plurality of the unidirectional microphones is zero, wherein each of the unit vectors faces a maximum sensitivity direction of each unidirectional microphone; and a calculation section for calculating an acoustic information vector by arithmetically adding each of the measurement values produced by the plurality of the unidirectional microphones of the sound reception section to produce an additional value, multiplying respective unit vectors by each of the respective measurement values to produce multiplied vectors, performing a vector addition of each of the multiplied vectors to produce a resultant vector, and performing a vector multiplication of the additional value by the resultant vector to produce the acoustic information vector.