A floor pump includes a main body and a supporting device. The supporting device includes a base and a first leg. The base is fixed to the main body and has a first stopping flange and a second stopping flange. The first leg is pivotally connected to the base to approach or move away from the base. The first leg has a front end and a rear end. When the first leg is approached to the base, the first leg is limited by the first and second stopping flanges to a folded position or an unfolded position. When the first leg is in the folded position, the front end is approached to the main body. When the first leg is in the unfolded position, the front end is distal away from the main body.