In an inventive cup luminous apparatus and its control method, the cup luminous apparatus is capable of luminescing in various colors corresponding to the fluid level of beverage put in a cup thus providing the cup with a light effect, detecting a proper consistency, a decay extent and an appropriate temperature of the beverage put into the cup, and then luminescing in mutually different colors based on its detection result, whereby a user may visually recognize a physical state of the beverage. The inventive cup also automatically flickers in case that the cup is slanted and is provided so as to be mounted more easily. The cup luminous apparatus includes a plurality of resistance detection elements installed on an inner wall face of the cup, for detecting resistance values changed by the water level, the consistency and the temperature change of beverage put into the cup; an analog/digital converter for converting analog signals detected by the resistance detection elements; light emitting elements for outputting light of mutually different colors from the inside of the cup towards the outside of the cup; and a controller for outputting a voice signal in response to an on/off state of the resistance detection elements, simultaneously outputting a toggle signal to the light emitting elements, and outputting a lighting signal to the light emitting elements in case a resistance value inputted from the analog/digital converter equals the proper consistency data and proper temperature data, and outputting a flicker signal to the light emitting element s in case the resistance value equals the decay consistency data and overheating temperature data; and a voice output element equipped in the cup and driven by the voice signal outputted through the controller.