OPTICAL DETECTION DEVICE AND BAR CODE READING DEVICE

PURPOSE:To simplify and facilitate signal processing in the part of a signal processing circuit by providing a signal generating means for generating a scanning end detection signal when a light beam is made to scan the end of a scanning region. CONSTITUTION:A light receiving system for monitoring the end of scanning is composed of photodetectors 20a, 20b arranged at both ends of a light scanning region and a start signal generating circuit 21, when the light beam (r) is made to scan either end and received by either of photodetector 20a, 20b, the start signal generating circuit 21 outputs a start signal (scanning end detection signal) to a signal processing circuit 7. The signal processing circuit 7 receives the start signal in synchronization with the timing for starting scanning when the light beam is scanned to the left and right end and a bar code signal for one signal between start signals. Consequently, the signal processing circuit 7 processes the bar code signal for one scanning partitioned by the start signal.