A pipe connection device according to the present invention includes: a connection member including a projection in which an insertion space is formed in the projection and a pipe is inserted through one side and which is bent in a circumferential direction at the other side and a separation preventing unit which is spaced apart from the projection and protrudes in the circumferential direction; and a flange member coupled to the circumference of the connection member between the projection and the separation preventing unit so as to contact the projection and having a joining hole penetrated by a joining member.