Resonance scattering by iron spheres in plaxiglass matrix is investigated numer ically. Based on the analysis of the zero and singular points of the scattered l ongitudinal and transverse wave coefficients, the absence of some resonance mode s is found to appear only in the scattered longitudinal wave modes of the lowest order. The absence of some resonance modes results from the fact that the zero points of the numerator and denominator of scattered longitudinal wave coefficie nts are located at the same positions in the complex frequency plane.