A road surface condition identification apparatus for identifying a road surface condition is provided. The road surface condition identification apparatus includes a vibration detector unit configured to output a detection signal being an analog signal according to magnitude of vibration of the tire. For identifying the road surface condition, the road surface condition identification apparatus performs A-D conversion of converting the detection signal of the vibration detector unit into a digital signal. Based on data on vehicle speed, the road surface to condition identification apparatus sets a conversion range of the magnitude of the vibration of the tire used in the AD conversion from the detection signal into the digital signal.