Of the signs in the musical notation, 'ㆆ' and '배' are among those signs of which meaning has not been interpreted yet. 'ㆆ' was put under the tones and '배' was used singly. These two signs were present only in the old notes contained in Jungganbo(sqare notation). The notes containing 'ㆆ' and '배' include "Sejongsilok Akbo" and "Daeakhubo". In the "Sejongsilok akbo", the two signs are seen in the Ⅰ and Ⅱ and the Ⅰ and Ⅱ. In the "Daeakhoobo", they are seen in such notes as Ⅰ and Ⅱ, Ⅰ and Ⅱ, , and . In the study, sign 'ㆆ' and sign '배' used in "Sejongsilok Akbo" and "Daeakhoobo" were interpreted, and the findings are as follows. The sounds having 'ㆆ'(glottalized Ieung sound) were mainly non-major sounds and used as weak sound. It was not used in the speedy notes in case the melody was trembled. '배'(Beo-i) is the sound that goes from a low tone (Beo) to a higher tone (i) and drags long.