Simple field monitoring system for optimizing and improving agricultural production process and management is developed by the built-in mail sender data logger unit with some weather and field monitoring sensors. In this monitoring system, all the monitoring data are once transferred and stored to mail servers. Thereafter the data are transferred periodically to the agricultural information database system. The database system was fully developed using open software such as apache (web server), MySQL, PHP, Java, CMS (Contents Management System) and so on. The stability of the monitoring system was verified using more than 20 monitoring units at four test sites where weather, crop type and farm size are different. On the other hand, work recording system to manage and optimize current production process was also developed and integrated to the developed database system. A list of farming processes and schedules was arranged flexibly by a farmer thorough a web browser. All the process data were entered into the information database by using mobile device and/or PC. The availability and validity of the developed recording system were verified by feasibility studies in the real farming sites.