Sticking of a substrate occurs in a reaction chamber for processing the substrate placed on a surface of a substrate-supporting device provided with lift pins for moving the substrate up and down with respect to the surface of the substrate-supporting device. A method of detecting the occurrence of the sticking of the substrate includes: monitoring a vibration propagating in or through the reaction chamber by a sensor, which vibration is indicative of or specific to sticking of the substrate on the surface of the substrate-supporting device when being moved up from the surface of the substrate-supporting device with the lift pins; and initiating a pre-designated sequence if the vibration is detected while processing the substrate in the reaction chamber.