An apparatus and method for unifying multiple radio frequency identifications (RFIDs) are provided. The apparatus includes: a data arithmetic operator collecting RFIDs, storing the collected RFIDs, and repeatedly performing the collection and storage when a time out event occurs; a hash arithmetic operator concatenating the RFIDs, hashing the concatenated RFIDs, and outputting a hashed single value; a random number generator generating a random number used as an encryption factor to public-key-encrypt the single value; an RFID tag processor controlling locking/unlocking of the RFID tags; a public key arithmetic operator public-key-encrypting the single value using a predetermined public key and the random number as encryption factors and outputting a cipher text; and a radio frequency communicator converting the cipher text into a radio signal and sending the radio signal to a radio section. Information transmitted to a radio section is a cipher text obtained by public-key-encrypting the single value. Therefore, the number of the RFID tags belonging to a user is not exposed to an eavesdropper, thereby protecting user's privacy.