The instrument used in hyperbilirubin therapy is phototherapy. The measurement of the blue light irradiation emitted by the phototherapy device is very important to know the strength of the phototherapy lamp so that the healing of hyperbilirubin can run optimally. The purpose of this study was to design a device "Radiometer as a Blue Light Irradiation Measuring Instrument on Phototherapy Equipped with Ultrasound HC-SR04 Sensor" which can be used in the calibration process or treatment of phototherapy devices. Phototherapy uses blue light lamps with a wavelength of 400-500 nm. The wavelength can be captured by the TCS3200 sensor. HC-SR04 ultrasonic sensor is used to measure the distance automatically when measuring the blue light irradiation value. The data collection method of the blue light radiation value on the phototherapy lamp was carried out at a distance of 30 cm, 40 cm, 50 cm, 46 cm at the right point, 46 cm at the center point, and 46 cm at the right point. Then the measurement results of blue light irradiation will be compared with the blue calibrator, namely Phototherapy Radiometer DALE 40/3728011. Based on the comparison data of irradiation values it can be concluded that between the author module and the calibrator has the smallest error value which is located at a distance of 46 cm in the middle point of 0.57% with an average difference of 4.33 μW / cm2. While the biggest error lies at a distance of 46 cm in the right point of 4.37% with an average difference of 23 μW / cm2. The relationship between distance and irradiation value is the closer the measurement distance, the greater the irradiation value and the largest measurement value at the left, middle and right measurement points is the center point. After testing the system as a whole, the author module can be used with its functions and purposes