A light, compact and low-cost liquid fuel reformer for removing the harmful substances within the exhaust gas discharged from vehicles having two magnet holding cases (3, 3') accommodating respectively anisotropic metallic materials (7, 7'). The magnet holding cases (3') and (3) are magnetically secured each other at respective commissure (3a, 3a'), pinching connecting tube (24) made of nonmagnetic material through which the liquid fuel flows. The magnetic fields generated by the anisotropic magnetic materials (7) and (7') are orthogonal to the connecting tube. The connecting tube has an outer tube (24A) made of nonferrous metal and an inner tube (24B) made of nonferrous metal. These two types of nonferrous metal are selected so as to generate an electric potential difference between the outer tube (24A) and the inner body tube (24B).