Two-stage kinetics of single-chain collapse was clearly observed by using a thinnest capillary-tube cell with a wall thickness of 0.01 mm and a diameter of 5 mm for dynamic light scattering (DLS) measurements. Two relaxation times, tau(crum) for the crumpled globule state and tau(eq) for the compact globule state, were determined for the first time. Experimental DLS data measured in the coil-to-globule transition were compared with theoretical predictions.