To evaluate the potential of a new breed, Suweon-511, antioxidant components and antioxidant activities of the 70% ethanol extracts of Suweon-511 (SWE) and Ilpum (IPE) were measured. Total polyphenol and flavonoid contents were 318.17 and 167.21 $\mu$g/g for SWE, which were higher than that of IPE (222.16 and 100.89 $\mu$g/g). Both $\alpha$- and $\gamma$-tocopherol contents were higher in SWE as well. The total tocopherol contents of SWE (1.31 mg/100 g) was higher than that of IPE (0.86 mg/100 g). The $\alpha$-, $\gamma$- and $\delta$-tocotrienol contents of SWE (0.10, 0.43, and 0.02 mg/100 g) that of IPE (0.09, 0.43, and 0.03 mg/100 g) showed little difference. For $\gamma$-oryzanol, Suweon-511, which contained 76.58 $\mu$g/g, contained ten times as much as I lpum (7.77 $\mu$g/g). The total antioxidant activity of SWE and IPE were 16.00 and 9.73 mg AA eq/g, respectively. For reducing power, at 5 mg/mL, both extracts were 0.18, but at 20 mg/mL, SWE showed 0.61 and that of IPE was 0.58. The DPPH radical, hydroxyl radical, superoxide radical and hydrogen peroxide scavenging activity of SWE were 42.00, 21.59, 23.27, and 17.13% at 5 mg/mL, and for IPE, they were 30.10, 22.37, 25.18, and 18.08%, respectively. These data, as well, did not show big difference between the two breeds. As indicated in the data above, the newly-bred Suweon-511 had higher content of antioxidant components compared to Ilpum, but similar or a little higher antioxidant activity.