An oven comprising: a housing having a cavity therein ; a radio wave generator coupled to the housing and configured to generate radio wave transmitted to the cavity ; a control unit electrically connected to the radio wave generator and configured to calculate radio wave information that is information related to intensity, phase, and frequency of the radio wave to be generated by the radio wave generator ; and a plurality of antennas electrically connected to the radio wave generator , and configured to allow the radio wave generated by the radio wave generator to be radiated into the cavity according to the radio wave information, wherein the plurality of antennas is spaced apart from each other, and wherein the control unit is configured to calculate the radio wave information with respect to each of the plurality of antennas . wherein the control unit comprises a signal detection unit configured to detect intensity, phase, and frequency of radio wave radiated into the cavity through each of the antennas , and intensity, phase and frequency of radio wave reflected from the cavity to the antennas . characterized in that the control unit comprises a reflection ratio calculation module electrically connected to the signal detection unit , and configured to calculate a reflection ratio at a specific frequency using the detected intensity of the radiated radio wave and the detected intensity of the reflected radio wave, and the control unit comprises a radio wave information calculation module electrically connected to the reflection ratio calculation module , and configured to compare the calculated reflection ratio with a preset reference reflection ratio and calculate a frequency of radio wave to be radiated into the cavity according to a result of the comparison. a housing having a cavity therein ; a radio wave generator coupled to the housing and configured to generate radio wave transmitted to the cavity ; a control unit electrically connected to the radio wave generator and configured to calculate radio wave information that is information related to intensity, phase, and frequency of the radio wave to be generated by the radio wave generator ; and a plurality of antennas electrically connected to the radio wave generator , and configured to allow the radio wave generated by the radio wave generator to be radiated into the cavity according to the radio wave information, wherein the plurality of antennas is spaced apart from each other, and wherein the control unit is configured to calculate the radio wave information with respect to each of the plurality of antennas . wherein the control unit comprises a signal detection unit configured to detect intensity, phase, and frequency of radio wave radiated into the cavity through each of the antennas , and intensity, phase and frequency of radio wave reflected from the cavity to the antennas . characterized in that the control unit comprises a reflection ratio calculation module electrically connected to the signal detection unit , and configured to calculate a reflection ratio at a specific frequency using the detected intensity of the radiated radio wave and the detected intensity of the reflected radio wave, and the control unit comprises a radio wave information calculation module electrically connected to the reflection ratio calculation module , and configured to compare the calculated reflection ratio with a preset reference reflection ratio and calculate a frequency of radio wave to be radiated into the cavity according to a result of the comparison. <EOS>