Vehicle height adjustment system

A vehicle height adjustment system operable to reduce a vehicle height adjustment time period without unnecessarily narrowing a vehicle height adjustment range is provided. A control unit adjusts the vehicle height of a vehicle by controlling supply and discharge of air to/from air springs each disposed between a side member and an under member. When the side member is at a vehicle height lowest position, a stopper of the side member comes into contact with a stopper receiving portion of the under member. When the side member is at the vehicle height lowest position while the control unit is set to a memory mode, an adjustment range setting section of the control unit sets a vehicle height lower limit by adding a lower limit setting predetermined value to a vehicle height measured value outputted from height sensors. The control unit does not lower the side member below the vehicle height lower limit during vehicle height adjustment.