PURPOSE: To treat fuel in a magnetic field extremely simply in existing automobile and small-sized burner by forming a tube by a blank, in which ferromagnetic-body impalpable powder such as ferrite is dispersed into an elastic body, such as a rubber, plastics or the like, and magnetizing the blank so that the magnetic field is generated in the tube.

CONSTITUTION: A tube is shaped by a blank, in which ferromagnetic-body impalpable powder such as ferrite is dispersed into an elastic body, such as a rubber, plastics or the like, and the blank is magnetized so that a magnetic field is generated in the tube. Fuel simply fitted into a path for fuel can be treated in the magnetic field by the magnetic tube. A gasoline tube connecting a fuel pump and a carbureter in a device such as existing automobile and motorcycle is replaced with the magnetic tube by this invention, thus treating fuel in the magnetic field extremely simply.