PURPOSE: To provide the titled equipment of improving fuel oil quality taking advantage of magnetizing action by vertical motion of the blades through the repulsive force between the magnets using as the agitating blades, permanent magnet itself.

CONSTITUTION: A sliding shaft 7 is set in the vertical direction along the vibration direction of the vessel, being fitted with, for example, three disc-shaped blades of permanent magnet 8. These blades are such that neighboring magnetic pole surfaces facing each other in the vertical direction represent the same pole of mutually repulsive nature. Thus, the lowermost magnet 8d descends to the lowest end of the shaft 7 under gravitation, while the magnet 8b at the middle tier float up in the air through the repulsive force against 8a, the uppermost magnet 8c floating further up in the air through the repulsive force against the magnet 8b. And, in response to the vertical vibration applied to the vessel 1 from the vehicle body, the magnets 8aW8c set in vertical motion leading to turbulence of the fuel oil with repeated extrusion and suction, thus accomplishing the objective improvement in fuel oil quality.