A digital signal receiving apparatus is disclosed. The digital signal receiving apparatus includes a main signal discriminating unit configured to discriminate a main signal of a received signal, a monitor signal discriminating unit configured to discriminate a monitor signal of the received signal, an error monitoring unit configured to monitor a discriminating error of the monitor signal discriminating unit, and a discriminating point control unit configured to control the discriminating points of the main signal discriminating unit and the monitor signal discriminating unit. The discriminating point control unit monitors an output of the error monitoring unit, moves the discriminating point of the monitor signal discriminating unit in the amplitude directions and the phase directions such that a discriminating error occurs, detects a center of discriminating points where errors are generated, and sets the detected center of the discriminating points as the discriminating point of the main signal discriminating unit.