A vehicle step device includes: a movable step that is provided in a door opening of a vehicle; and a drive controller that drives the movable step so that the movable step operates in deployment and storage directions. The drive controller includes a sidewalk detection unit that detects a sidewalk provided in parallel with a traveling road surface of the vehicle, a separation distance detecting unit that detects a separation distance between a side edge portion of the vehicle in which the movable step is stored and the sidewalk, and a deployment amount setting unit that sets a deployment amount of the movable step extending in a width direction of the traveling road surface from the side edge portion of the vehicle based on the separation distance. The deployment amount setting unit sets a deployment amount of the movable step to be larger as the separation distance increases.