The formation of rip currents affected by regularly arranged beach cusps has been investigated quantitatively using 2-dimensional Boussinesq type numerical wave simulation. The numerical model has nonlinearity, dispersion, wave runup on the beach and wave breaking effects. The rip currents are generated regularly at the edge of the each cusp. Shape of the beach cusp enhances the formation of rip currents. The rip current takes its maximum velocity at H/Lo=0.013 and corresponding surf zone similarity parameter 0.7-1.0. We found the constantly low water level point at the edge of the beach cusp.