Approximate expressions for calculation of light scattering amplitude by optically “soft” circular cylinder of finite length have been derived in Wentzel–Kramers–Brillouin approximation for the case of light incidence perpendicularly to the cylinder axis. Scattering phase functions (or f11 element of the scattering phase matrix) of an infinitely long circular cylinder (rigorous solution) and of a finite-length circular cylinder calculated in Wentzel–Kramers–Brillouin approximation have been compared numerically.