To operate a pillion step in one action. The pillion step is formed in a generally L shape and includes an arm portion and a foot rest portion. One end of the arm portion is pivotably secured through an oblique pivot shaft to a side face of a seat rail located under a rider seat and is pivotally moved around the oblique pivot shaft. When the pillion step is to be retracted and is pivotally moved backward, the foot rest portion moves into a gap between the rider seat and a pillion seat and its tip end is received within a grip space formed in a grip.