  Abundance of iron in the atmosphere of Arcturus has been determined from the
profiles or regions of the profiles of the weak lines sensitive to iron
abundance. The selected lines of Fe I and Fe II were synthesized with the MARCS
theoretical models of the atmosphere. From the observed profiles of lines
available with a high spectral resolution in the atlas by Hinkle and Wallace
(2005), the values of the iron abundance $A = 6.95 \pm 0.03$ and the
radial-tangential macroturbulent velocity $5.6 \pm 0.2$ km/s were obtained for
Arcturus. The same physical quantities were found for the Sun as a star; they
are $7.42 \pm 0.02$ and $3.4 \pm 0.3$ km/s, respectively. For Arcturus, the
iron abundance relative to the solar one was determined with the differential
method as [Fe/H] $=-0.48 \pm 0.02$.
