[en] The dependences of saturation magnetostriction λ_s and forced-volume magnetostriction δ ω/δ H on the concentration and temperature have been investigated for amorphous La(Fe_xAl_1-x)₁₃ alloys prepared by high-rate DC sputtering. The magnetic phase diagram obtained from the differential magnetic susceptibility dM/dH has been correlated with these magnetostrictions. The spin freezing temperature T_f is drastically decreased but the Curie temperature T_C is slightly increased on application of a magnetic field. The temperature dependences of λ_s and δ ω/δ H exhibit a broad peak at the spin freezing temperature T_f. The temperature dependence of λ_s for the ferromagnetic alloys is explained by the two-ion model, reflecting the peculiar amorphous structure consisting of icosahedral clusters. The peak of δ ω/δ H at the Curie temperature becomes indistinct with increasing ferromagnetic state in contrast with the peak at the spin freezing temperature. The giant values of δ ω/δ H and its divergent behaviour at the spin freezing temperature are accounted for by the variable amplitude of the local magnetic moment in the itinerant spin glasses. The significant large δ ω/δ H is connected with the pronounced large magnetovolume and magnetoelastic effects such as the spontaneous volume magnetostriction ω_s, compressibility κ and high-field susceptibility χ_hf which bring about various Invar anomalies. (author)