To manufacture a metallic tube having a socket part capable of easily applying a resin to an inner surface of a tubular body with excellent productivity by pouring a molten spheroidal graphite cast iron in a silica mold to cast the socket part, forming the tubular body part of a rolled steel plate to a specified length and to the same inside and outside diameters as those of a short tube at the socket part, and connecting a side surface of the short tube of the socket part to a tube end side surface of the tubular body part through the friction welding.

A flange type socket part 4 is cast of a spheroidal graphite cast iron, and a tubular body part 8 is manufactured of a rolled steel plate. A side surface of a short tube 3 of the flange type socket part 4 is connected to a side surface of a tube end 6 of the tubular body part 8 through the friction welding to form a metallic tube 12 having the flange type socket, and the other end of the tubular body part 8 is an insertion part 7. A connection part 10 is normalized through the direct energization heating or the induction heating to mechanically turn burrs on the outside of the tube of the connection part 10. Burrs on the outside of the tube of the connection part 10 are mechanically turned, and then the connection part 10 may be normalized.