Before and after the 1930s, considered the golden age of children's songs, the discussion on proletarian children's literature, actively developed in daily newspapers and magazines, demonstrates their aspiration and willingness to class music, i.e., agitprop art, for ideological struggle of the group of writers. So what was the reality of the songs based on the theory they pursued? This study attempts to reconsider their existence in the history of the children's songs in Empire Japan’s forced occupation period by comparing the discussions on the proletarian children's songs written in the daily magazine and the realities called songs. First of all, this study focusing on Song Wansoon's "proletariat theory of children's song" appearing in Chosun Ilbo, July, 1930, investigates the theory of children's songs to 'perform political missions as an artistic struggle' and the corresponding actual songs. Works of this trend can be seen in children's magazines such as "Sinsonyeon" and "Byeolnara", which have strong classism character at the time. Then this study checks out the songs listed in “Proletarian children's songs collection, Bul‐Byeol.” The character of some works that were duplicated in "Music and Poetry (Eumak and Shi)", a comprehensive art magazine published a little earlier than this children's songs collection, that is, the blatant rage and aggression against hostile class may have been seen in some parts to represent the Proletarian songs so far. But in the proletarian‐related children's songs that were sung as the actual songs, there were these attacks and punishments, as well as the hardships and sadness caused by the Japanese takeover and tyranny, and nevertheless, it can be seen that there were also realistic (overcoming) songs that dreamed of hope of the future. Also, although not known in the meantime, through Cho Kwangho’s works and explanations, a composer who appeared several times in "Byeolnara", at the time, nursery rhymes with lyric children's minds, emotions, depictions and imaginations of nature were found to be played at various gatherings of labor and peasants’ children. And while claiming the hierarchy of music and children's mind, in Shin Gosong’s works, who adhered to 'children's pure mind', the everyday and humorous children's mind songs came to the forefront. It is also consistent with the conclusion of Song Wansoon's proletariat theory of children's song, claiming that "We must sing everything". Proletarian children's songs originated from class socialism theory were not all political militant music located at the antipode of the pure angel children's mindism that was defined and separated since then. The aggression that has represented proletarian children's songs due to some aggressive texts is only its part and in the actual songs, it is confirmed that the proletarian children's songs sang the environment and emotions, laughter, fun, and 'children's mind' surrounding the human children. In the 1930s, when children's songs were considered to be the growth period of the creative children's songs, while being inclined to sentimentalism or reading the situation without realizing the reality, at a time when they could only achieve quantitative growth by pursuing the illusion of vaguely naïve children's mind, the proletarian children's songs movement, driven by a willingness to recognize and overcome the reality, a passionate passion for criticism and struggle, certainly had a meaningful role in the history of modern children's songs.