The objective of this paper is to obtain the contribution of each source to the spectrum of pressure, when there are multiple incoherent sources in near-field acoustic holography. For this objective, we have to obtain signals very coherent to the input signals of the sources. To obtain the very coherent signals, many people have measured pressure signals in the vincinity of the sources. However, it is sometimes difficult to locate microphones near to the sources so that the signals are very coherent to the input signals. This paper proposed a method to obtain the very coherent signals by near-field acoustic holography. Therefore, the proposed method does not require the measurement of pressure near to each source. Simulation results for two incoherent monopole sources showed the possibility of the proposed method.