To mold plural concave parts of a precise shape in a pipe by a press processing, without applying a cutting processing, whose mass is light in weight, and whose processing expense does not go up.

This method is provided with a charging process (ST1) for charging a low melting point alloy in a pipe as a core bar, a clamping process (ST2, ST3) for clamping a point other than the portion where the concave part is molded on the pipe peripheral face with a clamping die, a pressurizing process (ST4) for pressurizing the low melting point alloy charged inside the pipe by pressing it from the pipe end part and, a concave part molding process (ST5) for molding a given contour shape on the pipe wall by pushing a molding punch to the pipe. According to the position and number of the concave parts to be molded in the pipe (ST8), the clamping process (ST2, ST3), the pressurizing process (ST4) and the concave part molding process (ST5) are repeated by moving the pipe in an axial direction and in an axis rotation direction against the clamping die and the molding die. After then, a process (ST9) for heating the low melting point alloy in the pipe into fusion and discharge them from the pipe is provided.