Experimental and numerical study on the effect of wavy leading edge (WLE) on pitching rectangle wings were conducted using NACA 0018 airfoil. The shape of WLE is sinusoidal function. URANS simulations were employed using SST k-ω turbulence model. The WLE wing has preferable forces at the post-stall region compared to baseline wing. The lift force improvement at upstroke motion was higher than downstroke motion, whereas the drag increase was found to be less than the lift increase. The numerical simulation clarified that stall is suppressed during pitching motion of the WLE wing.