A memory management apparatus has an ASID conversion table, an actual ASID use table, and a TLB flush control section. The ASID conversion table and the actual ASID use table manage virtual ASID, actual ASID and an overlap flag so that they are related for each VM. The TLB flush control section reads actual ASIDs allocated to VM as a switching target at the time of switching VM as a switching source into the VM as the switching target, determines whether the read actual ASID is allocated to the plurality of VMs in an overlapped manner with reference to the overlap flag, and sets the actual ASID in the read actual ASIDs determined being allocated in the overlapped manner as a target for the TLB flush.