Arnold Scho¨nberg used three twelve-tone series in the first movement of his 「String Quartet no.3」. These twelve-tone series are used in both melodies and accompaniment. But sometimes he did not follow this fundamental rule to pursue musical thought even though he made use of the twelve-tone system in this piece. This thesis is focused on not only theme melodies, but also first ostinato motive of accompaniment and the relationship of balance between Scho¨nberg's primary and secondary musical thought can be considered in the theme melodies and the first motive of accompaniment. That is to say, Scho¨nberg shows how the main melodies and the supported ostinato motives match well together from the examples of his own musical main thought, environs thought, and relative thought. This is an specific example that Scho¨berg can develop his musical logic in his piece perfectly only when all of musical elements are in harmony. This is different with tonal music which is depends on the development of just main melody. Scho¨nberg says that the meaning of composition skill of the twelve-tone system is a reproduction of the traditional tonal harmony and is for systematization of the process of entire musical elements. So, he unites between the traditional composition techniques with and his twelve-tone system. 「String Quartet no. 3」 is also composed using both old and new. Unusually, there was no sensation in the first performance of the 「String Quartet no. 3」. But his critics said Scho¨nberg could not overcome his fantastic musical theory deeply and this piece was an expression of the Dadaism.1」 However, When it was performed at Frankfurt in 1928, Adomo was fascinated with this 「String Quartet no. 3」 and he evaluated this piece as a 'very influential music'. The article 「Why is it difficult to understand Scho¨nberg's music」 of Alban Berg says several common characteristics of atonal music. these characteristics include similar variety of harmonies, various methods of cadences, equal use for each tone in twelve-tone system, well-matched harmonies with melodies, unsymmetrical and unlimited composition in musical theme, abundant variation skills, inclusive polyphony, and various and subdivisible rhythms. Scho¨nberg's 「String Quartet no. 3」 uses abundant various rhythms, variation skills with motive, counterpoint skills, and musical theme development based on traditional harmonic function. This piece includes various characteristics of atonal music which Alban berg notes in his article. Scho¨nberg's 「String Quartet no.3」, composed with abundant musical skills, shows the serious musical thought of the composer and his musical beauties. This breaks general opinions that Scho¨nberg's piece is difficult to understand.