The present invention allows immediate reading of a monitor voltage of a required arbitrary burst cell and provides a burst light receiving power monitor circuit that monitors the monitor voltage of a burst cell, the burst light receiving power monitor circuit comprising: a memory that includes a plurality of areas and that prepares an address for each area; a monitor voltage forming section that converts input signal light of the burst cell to a digital monitor voltage amplitude; and a controller that continuously stores the monitor voltage amplitude from the monitor voltage forming section in each area of the memory specified with an address by a control signal externally inputted according to the timing of the burst cell and that controls reading out a monitor voltage from an arbitrary area of the memory specified with an address by an external memory access signal.