A vehicle height adjustment device includes front forks, a rear suspension, a weight estimation unit, and a front wheel-side target movement amount determination unit. The front fork includes a front wheel-side suspension spring and a front wheel-side support member, which supports one end of the front wheel-side suspension spring, and moves toward another end of the front wheel-side spring to change the front wheel-side suspension spring length. The rear suspension includes a rear wheel-side suspension spring and a rear wheel-side support member, which supports one end of the rear wheel-side suspension spring, and moves toward another one end of the rear wheel-side spring to change the rear wheel-side suspension spring length. The weight estimation unit estimates a weight applied to a vehicle. The front wheel-side target movement amount determination unit decreases, a movement amount of the front wheel-side support member as the estimated weight increases.