To reduce work locations of a steering stem to facilitate the work in a clamping structure of the steering stem of a straddle type vehicle.

In the clamping structure of the steering stem of the straddle type vehicle, a diameter I of a handle stem connection part 34 provided upper than a screw part 33B that is clamped by a lock nut is provided smaller than the diameter J of the screw part 33B, and the diameter of a circle that takes as the diameter, a line L1 that reaches an inner edge of a stem washer 50 through the center O of the stem washer 50 from the center part tip 56A of an engaging projection 56 of the stem washer 50 is provided to become larger than the diameter I of a handle post connection part 34. The inner diameter of the stem washer 50 is provided to become equal to the diameter J of the screw part 33B of the steering stem 30, and a groove 35 of the steering stem 30 is provided only in the neighborhood on an upper part nut 45 of the steering stem 30.