A rollator is disclosed in this invention. The rollator includes: a base frame; front wheel assemblies and rear wheel assemblies respectively mounted on both sides of the base frame; an inverted U-shaped supporting pipe; a H-shaped armrest bracket; connection pieces having block grooves thereon; a slide control lever for cooperating with the block grooves; a seat plate; a spring element; wherein the base frame is provided with unidirectional hinged seats; both bottom ends of the supporting pipe are hinged to the base frame, and both side arms of the supporting pipe are provided with slide holes facing each other; the armrest bracket has bottom portions hinged to the unidirectional hinged seat. The rollator has a simple structure and can be used for various situations in both folded and unfolded state.