A rolling base comprises, for use, a pair of fastening plates for fastening to a foot of the mast, each plate having a symmetry axis; —three arms, each having an orientable castor, including one fixed arm in the extension of the symmetry axis of the plates, and two swivelling arms symmetrically arranged on either side of the fixed arm. Each plate comprises on each side of the symmetry axis at least three means for locking the swivelling arms in three different angular positions relative to the symmetry axis. For storage, each swivelling arm is parallel to the fixed arm and to the symmetry axis of the plates. For transport under load, each swivelling arm forms an angle to the symmetry axis of more than 105°. For vertical fastening position, each swivelling arm forms an angle to the symmetry axis of more than 90° and less than that in transport.