PROBLEM TO BE SOLVED: To provide an earthquake-resistant and rainfall-resistant measure slope stabilization method for an earth structure using a small-diameter square rod-like reinforcement body, which prevents devastating destruction while allowing a certain level of deformation.SOLUTION: In an earthquake-resistant and rainfall-resistant measure slope stabilization method for an earth structure using a small-diameter square rod-like reinforcement body, natural ground reinforcement earth work 3 using a natural ground reinforcement material made of a small-diameter square steel pipe 11, a cell-type reinforcement slope protection work 1 including laying of a geocell subjected to filling work, and head anchorage work 4 for the natural ground reinforcement material and the geocell are applied to increase efficiency of work with an excavator.