To provide a method of restricting and cutting pipes without using a dedicated tool corresponding to the structure of the pipes with a plate material.

The pipes 1 with the plate material is provided with such a structure that both ends of U-shaped pipes 3 are fixed to one face of the plate material 2, a plurality of pipes are aligned in parallel at some interval apart to form a pipe group 4 and a single step of the pipe group or two steps or more are provided on one face of the plate material at some interval apart in the inside/outside direction. This cutting method of the pipes 1 with the plate material is characterized in fastening the respective pipes of the pipe group in the same step with a flexible string material 5 along the alignment direction of the pipes, tensioning the string material between adjacent pipes to restrict the whole pipes on the same step, and operating the cutting tool 6 in the alignment direction of the pipes at a position near the string material to cut the pipe group.