The folktale of \'AGICHANGSU(아기장수 : Baby Warrior)\' is the story that a extraordinary baby is killed by his parents, relatives, or neighbors. The folktale has been handed down at many regions in Korea for a long time. It is very typical story and power sustaining its tradition is also strong. In this story, Baby\'s death is caused by his mother. Considering universal sense that the relation between mother and son is the root of all the human relation and the mutual affection is the most original human emotion, the theme of this folktale is contrary to general human feeling.-\'infanticide by kin\' is one of the mythological motifs. In addition the family relation is attached great importance to in traditional agricultural society. It is important that nonetheless many people have sustained oral tradition of the story and have reserved the moral judgement of his death. Though traditional storytellers have thought his death an injustice, they have kept telling the folktale without varying the story. The essential meaning is induced from the conscious tension between considering his death as an inevitability and opposing killing him. And the meaning offers some senses about problems brought in any time concerning essential conditions of human-being. These senses are concerned with mythological theme. There are three mythological motifs in the folktale of \'AGICHANGSU\'. They are \' demigod\', \'initiation\', and \'sacrifice-mechanism\'. \'AGICHANGSU(아기장수 : Baby Warrior)\' has both attributes of God and attributes of Human, so he is a \'demigod\'. \'Demigod\' in mythic narrative symbolizes the contradiction and the limitation of human being that has been independent of God recognizing himself as human being though he has kept longing the complete and entire world of God. It represents the ontological conflict and the conversion of the ontological thinking. His death represents \'initiation\'. The motif of \'infanticide by mother\' symbolizes the initiating process that a child becomes independent of his mother and is born again as social-being mentally. And the oral narration is supposed to be a kind of initiation itself. Most oral narrators of this folktale listen to the story in childhood. And his death presents \'sacrifice-mechanism\', considering that he is regarded as the cause to drive the group into a crisis and is killed by a social group. In social context this motif is interpreted as the violence of the minority by the majority and as constraint of the social identification. He is killed by members of his own society because he is different from other members except himself, so it presents the mental conflict between group consciousness and individual consciousness.