The present invention relates to an apparatus for sensing and controlling the amount of gas supply and a method for sensing and controlling the amount of gas supply thereby, wherein the apparatus is capable of continuously maintaining the originally set amount of gas supply while, on the basis of the number of bubbles generated by any set time difference at the time when the target gas flows in the tube, the supply amount of the corresponding gas is being sensed in real time using a light sensor, thereby differentiating the accurate supply amount and the faulty or not of the supply state, and wherein a series of automated devices are allowed to control the pressure of the tube in real time such that the target supply amount can be precisely realized according to the gas supply information obtained from the light sensor, thereby actively preventing the malfunction. The apparatus comprises: a tube (1) for allowing target gas to flow from the bottom to the top； a sensing unit (10) engaged to the external surface of the tube, wherein the sensing unit senses the number of bubbles of the target gas, which sequentially moves for a predetermined period of time in the inner space of the tube, in real time by applying the light sensor according to the signal information of a light emitting diode and a transistor positioned to face each other； a controller for receiving the bubble information from the sensing unit to determine whether the bubble information matches the target amount of gas supply in consideration of the previously set time； and a pressure adjustment unit (20) operated by signals obtained from the controller, and determining whether the inner space of the tube is blocked in a manner in which the pressure adjustment is rotated at an angle proportional to the number of pulses given through a motor, thereby varying the number of bubbles during any period of time to match the target amount of gas supply.본 발명은 튜브 상에서의 대상 기체 유동시 임의 설정된 시간 차로 생성되는 기포 횟수에 기인하여 해당 기체의 공
