A step structure of a saddle-ride type vehicle is configured to permit easy adjustment of a position and also of an angle of a step. A pair of opposed clamp pieces, that are formed as part of a step-support bracket provided to a vehicle body of a saddle-ride vehicle, are provided to sandwich an eccentric collar (rotor) from both sides thereof in a radial direction. The clamp pieces are configured to be tightened against the eccentric collar by a bolt, thereby non-rotatably fixing a position of the eccentric collar. The eccentric collar is configured such that when the clamp pieces are loosened, a shaft part of a step is pivotally movable in relation to a shaft insertion hole, and the step, supported by the shaft insertion part, can be adjustably rotated in relation to the step-support bracket.