The concern of structural coherence in a musical composition has been applied since Medieval Ars Nova with its methodical isorhythmic writing; the trend then continued to the next generation of composers, especially Beethoven and his Symphony number five, in which the whole piece is built upon four-note simple pattern. Piano composers in the nineteenth century heightened this coherence concept while searching for new inspirations for dramatic purpose. Robert Schumann (1810-1856) is reputable as a concert pianist in the nineteenth century, who associated himself with the current development of literature at that time. His most important legacy is the creation of a new genre called as piano cycle which consists of a number of movements derived from the same extra musical resources. However, Schumann never gave any instruction for the movements in a work to have been performed together as a cycle (except the Fantasiestücke, Op. 12), which was planned as a complete unit as stated as Maurice Hinson. The purpose of this research is to analyze various elements in the Carnaval, Op. 9 (21 numbers, 1883-5) that function as unifying devices, hence leading to the conclusion that this work should be performed as a completely unified cycle. After doing in-depth study of this work, the author finds five unifying elements, concluded as follows: the significance of “the number of two;” hemiola; dotted rhythmic figure; repetitive figure; and A-S-C-H motive.