Abstract: A gas-supply regulating device for use in a gas burner assembly, includes a housing defining a first delivery port communicated with a first burner tube, a second delivery port extending radially, and a gas inlet extending radially, a valve member rotatably disposed within the housing and provided with a duct unit such that rotation of the valve member results in shifting of gas supply of the gas inlet to different modes, and an actuator operable to rotate the valve member and to be shiftable between retained and released positions. Thus, the size of flames from the first and/or second burner tubes can be adjusted to meet the user's requirement during barbecuing.