An upgraded submerged Doppler-type directional wave meter can measure 10 wave quantities related to directional wave motions, i.e. water surface elevation, 3 components of water particle velocities at each layer of 3 different water depth ranging from shallow to deep. In this study, accuracy of directional spectrum estimation is comprehensively investigated for various cases where directional spectra are estimated with various sets of different number of wave quantities. As a result, accuracy improvement is generally confirmed in various wave conditions when all the quantities are applied to the estimations, compared with the cases where conventional 4 wave quantities are applied to the estimations. Moreover, the advantage of BDM with the improved computation method was confirmed.