The browsing room of our library at National Fisheries University has been without a visitor counting system. So, we constructed an inexpensive counting system using a network camera which can send the caputured images of visitors to a pc through a network where the captured images can be seen. In our system, the counting of visitors in these images is done by a human because our browsing room seldom has more than a hundred visitors in a day. After a few months operation of the system, it turned out that the count by our system is very accurate but achieving the accuracy needs some concentration of a human.