A discharge lamp bulb includes an arc tube having: a pair of electrodes that are opposed to each other inside a luminous tube; an outer tube having the luminous tube therein; a pair of lead wires connected to the electrodes; and a metal band mounted on an outer periphery of the outer tube, a support plug having: a plug body having a hollow, inner cylindrical section therein that opens at a front end; an arc-tube support portion mounted on a front-end edge of the inner cylindrical section; and a flange, and a lead support wire extending outside the outer tube in the longitudinal direction and connecting one of the lead wires with the support plug, wherein a front-end face of the inner cylindrical section is substantially flush with a front-end face of the flange or positioned on a back-end side with respect to the front-end face of the flange.