A retractable bar includes an inner tube, an outer tube and a positioning assembly. The outer tube has a longitudinal sliding groove and multiple locating notches. The outer tube is axially movably sleeved onto the inner tube. The positioning assembly has a positioning block and a press button. The positioning block is accommodated in the longitudinal sliding groove, and the positioning block has a positioning protrusion and a threaded hole. The press button has a threaded portion engaged with the threaded hole and is movable between a first position where the positioning protrusion is forced into engagement with one of the locating notches to lock the outer and inner tubes and a second position where the positioning protrusion is disengaged from each locating notch for allowing the axial relative movement of the outer tube to the inner tube for adjustment of the length of the retractable bar.