A developing agent filtering apparatus includes a filtering arrangement for filtering magnetic toner from the mixture of the magnetic toner and foreign matter. The filtering arrangement includes a pair of magnetic field generating members, and a filter for regulating a shifting movement of the foreign matter from one of the pair of magnetic field generating members to the other; and a switch for changing the configuration of a magnetic field generated by the pair of magnetic field generating members. The switch switches a relative position between the pair of magnetic field generating members between a first position where opposite magnetic polarities of the pair of magnetic field generating members are opposed to each other and a second position different from the first position.