Since ancient times in Europe, stories have been told about heroes, gods and saints who fought with dragons. While many of them faced monsters and killed them, there are some stories of heroes and heroines who were swallowed by a dragon, killed it from inside, and emerged unhurt from its body. Some of the pictures and legends from the ancient or medieval times tell about those dragon-slayers. For example, according to a picture on a vase of the 5th century B.C., the famous Greek hero Jason was swallowed apparently by a dragon and came out again of its mouth. A legend also tells that the Irish hero Fionn Mac Cumhail entered the body of a dragon and killed it from inside. We can also find the similar motif in the medieval paintings and the legend of St. Margaret. The meaning of those pictures and legends seems difficult to understand. I analyzed the motif of the "swallowing dragon" by applying it to the scheme of rites de passage. According to Arnold van Gennep, the rites of passage consist of three steps-separation, transition, and incorporation. It is also said that they symbolize the death and rebirth of a person who moves from one state to another. I viewed that the motif of the "swallowing dragon" represents the death and rebirth at the rites of passage of heroes or saints. At the beginning of the article, the pictures and stories of the "swallowing dragon" are presented. After that, I will compare the European "swallowing dragon" stories with the notion of the "swallowing animals" in other countries (they appear at the initiation of Siberian and Eskimo shamans as well as the people of New Guinea) and examine the analogy between them. Then, I will apply the Genneps schema to "swallowing dragon" stories and consider whether we can count them among the rites of passage. With the results from those studies, I will clarify the notion of death and rebirth in the European pictures, myths and legends.