A blanking device for multi-beams includes arrayed plural separate blanking systems, each performing blanking control switching a corresponding beam of multi charged particle beams between a beam ON state and a beam OFF state and each including a first electrode, a first potential applying mechanism applying two different potentials selectively to the first electrode for the blanking control, and a second electrode performing blanking deflection of the corresponding beam, the second electrode being grounded and paired with the first electrode, and a potential change mechanism changing a potential of the second electrode from a ground potential to another potential, wherein when a potential of the first electrode included in one of the separate blanking systems is fixed to the ground potential, the potential change mechanism changes the potential of the second electrode corresponding to the first electrode fixed to the ground potential, from the ground potential to the another potential.