Phytochemical examination of the barks of Actinidia arguta led to the isolation of five flavonoids. Structures of compounds were elucidated as catechin (1), (-)-epicatechin (2), quercetin (3), $quercetin-3-O-{eta}-D-glucopyranoside$ (4), $quercetin-3-O-{eta}-D-galactopyranoside$ (5) by comparison with previously reported spectral evidences. To investigate the anti-oxidative effect and nitric oxide (NO) production inhibitory activity of these compounds, DPPH radical scavenging activity and nitric oxide production inhibitory activity in $IFN-{gamma}$, LPS stimulated RAW 264.7 cell were examined. The $IC_{50}s$ were determinied as follows : $1;$IC_{50}=26.61;{mu}g/ml$, $2;IC_{50}=25.30;{mu}g/ml$, $3;IC_{50}=20.41;{mu}g/ml$, $4;IC_{50}=18.23;{mu}g/ml$ , $5;IC_{50}=30.46;{mu}g/ml$, $6;IC_{50}=28.0;{mu}g/ml$, $7;IC_{50}=27.24;{mu}/ml$. These NO production inhibitory effects were significantly different compared with the positive control, L-NMMA $(IC_{50}=20.77;{mu}g/ml)$, respectively. Compound $1;(IC_{50}=6.19;{mu}g/ml)$, $2;(IC_{50}=8.98;{mu}g/ml)$, $3;(IC_{50}=7.30;{mu}g/ml)$ and $4;(IC_{50}=7.64;{mu}g/ml)$ also showed potent antioxidative activities similar level to ascorbic acid $(IC_{50}=9.22;{mu}g/ml)$. These results suggest that barks of A. arguta have a potent anti-oxidative and anti-inflammatory activity.