The present invention amplifies and processes a pulse-type input signal driven by an optical signal, such as a pulse oximeter or oxygen saturation, to obtain a high signal-to-noise ratio by removing the ambient signal caused by ambient light. An automatic offset calibration device based on a binary search of an oxygen saturation meter, the LED driving unit generating a current, the light emitting unit receiving the current generated from the LED driving unit and emitting light, and reflected from the blood vessels inside the finger approaching the light emitting unit A detection unit that detects light and converts it into a current, outputs the current converted by the detection unit, converts it into a voltage, amplifies and outputs a current-voltage conversion amplification unit, and converts and amplifies the current-voltage conversion amplification unit. A sampling and filtering unit that receives the voltage and samples and filters the output, a digital converter that receives the filtered voltage from the sampling and filtering unit, converts it into a digital value, and outputs the output signal of the current-voltage conversion amplifier unit. A comparison unit that receives and compares whether it is positive or negative, a binary search logic unit that searches binary search logic based on the comparison result of the comparison unit, and outputs the value of the output signal of the current-voltage conversion amplifier unit near O, and the binary search Characterized in that it comprises a current converter for converting the value retrieved from the logic unit to an analog value and outputting the current-voltage converter to the amplifier.본 발명은 펄스 옥시미터(pulse oximeter) 또는 산소 포화도와 같이 광신호로 구동되는 펄스 형태의 입력신호를 증폭하여 처리할 때 주변광으로 인한 배경신호(ambient signal)를 제거함으로써 높은 신호대잡음비를 획득하도록 한 산소포화도 측정기의 이진검색 기반 자동 오프셋 교정장치에 관한 것으로서, 전류를 발생하는 LED 구동부와, 상기 LED 구동부로부터 발생된 전류를 받아 발광하는 발광부와, 상기 발광부로 접근한 손가락 내부 혈관에서 반사된 빛을 검출하고 전류로 변환하여 출력하는 검출부와, 상기 검출부에서 변환된 전류를 전달받아 전압으로 변환하고
