The gold adsorption effect on the distribution of monatomic steps on the (111) silicon surface is studied in situ by ultrahigh vacuum reflection electron microscopy at temperatures of 850-1260°C. A new effect of the instability of silicon surface morphology has been detected. This effect leads to the redistribution of regular steps (RSs) to step bunches (STs) and vice versa on a surface covered with a gold submonolayer. For the crystal heated by directly passing an electric current, the behavior of the RS ⇔ SB morphological transitions on the silicon surface is investigated as a function of the gold coverage and the direction of the heating current. Thus, isothermal annealing at 900°C is accompanied by the following transitions on the silicon surface with predeposited 0.75 monolayer gold coverage: RS (0.72) ⇒ SB (0.42) ⇒ RS (0.24) ⇒ SB (0.07) RS ⇒ (0). The numbers given in parentheses are estimated values of the critical gold coverage measured in the monolayers at which the morphological transitions are observed. A change in the direction of the electric current used to heat the crystal leads to the reversible changes RS ⇒ SB and SB ⇒ RS at the same values of the critical gold coverage.