An apparatus and method for passive radio frequency identification (RFID) reader digital demodulation with respect to a Manchester subcarrier signal are disclosed. In a passive RFID environment where the Manchester subcarrier signal contains DC components in a frequency region, even when a tag signal containing the DC offset noise is input to a baseband, demodulation may be efficiently performed while the DC offset noise is removed. Therefore, accurate detection of tag information from the tag signal may be achieved.