A packet filtering apparatus for filtering a packet transmitted from a mobile node to a correspondent node in a network system using Mobile Internet Protocol (IP). The packet filtering apparatus includes a next header reader for reading a next header of the received packet to determine whether it is a mobility header, a mobility header type reader for reading a mobility header type when the next header is the mobility header, a mobility option reader for reading a mobility option added by the mobile node, and a packet rule applier for determining whether a home address included in the mobility option read by the mobility option reader is identical to a source address stored in a packet filter rule, and determining whether to pass the packet according to the determination result.