The development of a transducer array for acoustical holography is described. The array consists of la 4x4 sparse planar projector array and a 32x32 dense planar hydrophone array. The elements of the proje- ctor array are "Diced and Shaded Transducers" and those of the hydrophone array are "Short-column and On-socket type Transducers". These are operated at 200kHz below the resonance frequency in the sea. Gain-phase deviations in the elements of the array determine the background noise to the holographic image signal. We realized that the standard deviation of responses was 1. O dB for the projector elements and 1. I dB for the hydrophone elements. Consequently, it is expected that the performance of the manufactured array gives an image with high quality.