We investigated V-V hiatus through J-ToBI labeling and listening to whole phrases to estimate degree of discontinuity and, if possible, to determine the exact boundary between two phrases. Appropriate boundaries were found in most cases as the maximum perceptual score. Using the open quotients OQ of electroglottography (EGG), pitch mark and spectrogram, the acoustic phonological feature of these V-V hiatus was found as phrase-initial glottalization and phrase-final nasalization, as well as phrase-final lengthening and phraseinitial shortening of the morae. A small F0 dip was observable at the boundary of V-V hiatus was found as universal indication of glottalization. The test materials are taken from the "Japanese MULTEXT", consisting of a particle - vowel (36), adjective - vowel (5), and word - word (4).