A suction brush for a vacuum cleaner includes an upper casing, a lower casing coupled to the upper casing and provided with a suction port through which contaminants are drawn in from a surface to be cleaned, a lift plate disposed between the upper casing and the lower casing to move up and down with respect to the lower casing, a lift plate driving part to allow the lift plate to move up and down, and a lift control unit to control the lift plate driving part so that when the surface to be cleaned changes from a hard floor to a carpet, the lift plate is raised, and when the surface to be cleaned changes from the carpet to the hard floor, the lift plate is lowered.