[en] The relative values of the oscillator strengths of thirty-one spectral lines of atomic thulium have been measured by Rozhdestvenskii's method of hooks. The lines originate in transitions from the 4f/sup 13/ 6s²²F⁰ /sub 7;2/ ground state of Tm I. Using a high-frequency discharge to populate the lower excited levels of the atomic thulium, relative values of the oscillator strengths of the eighty strongest absorption lines of Tm I were determined by the same method. These lines arise in transitions from the 8771-cm/sup -1/, 13,119-cm/sup -1/, 15,271-cm/sup -1/, 15,587-cm/sup -1/ and 16,456-cm/sup -1/ levels. The relative f number values of spectral absorption lines originating from the 4f/sup 13/6s²²F⁰ /sub 7;2,5;2/ levels of Tm I, which were converted to absolute values with the aid of data on the lifetimes of the excited states of atomic thulium, were obtained by Wallenstein's method of intersecting levels