A packet communication monitor used for radio packet communication system having computer with display, comprises means for detecting and storing electric field strength data while receiving frame with time series, means for detecting and storing data of a start time and an end time of the receiving said frame, and means for checking and storing correct/error status data of said frame in time series. On the bases of these stored data, said packet communication monitor is able to display waveform of the electric field strength, and the length and the status of correct/error of said frame graphically and simultaneously.