To provide a microvalve which can be easily miniaturized and integrated in extremely simple construction with high durability for stable and reliable valve opening/closing operation without giving damage to the valve even when there is a great pressure difference between an inlet and an outlet for fluid having high pressure and high viscosity or the valve.

The flow amount of non-magnetic fluid which flows in flow paths A, B when a minute ball 2 moves to a first position is less than the flow amount of the non-magnetic fluid which flows in the flow paths A, B when the minute ball 2 moves to a second position. Thus, the microvalve can be easily miniaturized and integrated in extremely simple construction with high durability for stable and reliable valve opening/closing operation without giving damage to the valve even when there is a great pressure difference between the inlet and the outlet for the fluid having high pressure and high viscosity or the minute ball 2.