In a vehicle bumper structure, an optical fiber sensor (32) is provided on the upper portion of the front surface of a front wall portion (30A) of a front-bumper reinforcement (30). A front-bumper absorber (28) is provided before the optical fiber sensor (32) and a load transfer plate (34) is disposed between the front-bumper absorber (28) and the optical fiber sensor (32). The vertical width (B3) of the front-bumper absorber (28) and the load transfer plate (34) are greater than the vertical width (B1) of the optical fiber sensor (32), and a lower end portion (34A) of the load transfer plate (34) extends below the lower end of the optical fiber sensor (32). Accordingly, when the optical fiber sensor (32) is offset to the upper portion of the front-bumper reinforcement (30), the front-bumper absorber (28) will not topple down and the impact load is input to the optical fiber sensor (32) even if the input direction of the impact load is slightly inclined.