[en] Double beta decay of ¹⁰⁰Mo to the excited states of daughter nuclei has been studied using a 600 cm³ low-background HPGe detector and an external source consisting of 2588 g of 97.5% enriched metallic ¹⁰⁰Mo, which was formerly inside the NEMO-3 detector and used for the NEMO-3 measurements of ¹⁰⁰Mo. The half-life for the two-neutrino double beta decay of ¹⁰⁰Mo to the excited 0₁⁺ state in ¹⁰⁰Ru is measured to be T_1/2=[7.5±0.6(stat)±0.6(syst)]⋅10²⁰ yr. For other (0ν+2ν) transitions to the 2₁⁺, 2₂⁺, 0₂⁺, 2₃⁺ and 0₃⁺ levels in ¹⁰⁰Ru, limits are obtained at the level of ∼(0.25–1.1)⋅10²² yr