A vertical adjuster for a suspending lamp comprises a cylinder at an upper end of the lamp; an inner upper side of the cylinder having a threaded section; a lead wire having one end connected to the lamp and being positioned at a bottom of the cylinder; another end of the lead wire being fixed to a retainer; an adjuster formed by a seat and a slidable annular block; a center of the seat having a hole; the seat being locked to an upper end of the cylinder; the slidable annular block having an axial hole; a lateral side of the slidable annular block having a radial screw hole communicated to the axial hole; a screw unit being located in the screw hole; a cross section of the slidable annular block being slightly larger than that of the hole and the slidable annular block being located below the seat.