Provided is an antenna for a Radio Frequency Identification (RFID) reader using an electrical loop. It includes an upper metal plate which functions as a radiator; a lower metal plate which is disposed apart from the upper metal plate by a predetermined distance and functions as a radiator; a ground plate disposed apart from the lower metal plate by a predetermined distance; and a feeding probe disposed at the center of the upper and lower metal plates. The antenna can perform radiation parallel to the earth's surface including other directions. Therefore, it is suitable for an RFID reader which recognizes an RFID tag attached in parallel to the earth's surface. The electrical loop antenna can control impedance matching, resonance frequency, antenna gain, and radiation pattern according to the distance between metal plates, size of the metal plates, thickness of a feeding probe, and how the metal plates are arranged.