Particle outflow measurements are carried out by the double-probe method during high-power neutral-beam injection into the JFT-2 tokamak in order to study the particle confinement characteristics. The particle confinement time τp, the trapping efficiency for particles, 1–R, and the limiter edge electron temperature are determined from these measurements. It turns out that density clamping is mainly due to a decrease in the re-cycling rate.