The water requirement of transplanting culture(TC) consisting of 16 plots and direct seeding culture in a well-drained paddy field(DC) also having 15 plots were measured in order to clarify the influence factors on water requirement. Each plot was maintained under different cultivation conditions. Those varied cultivation conditions were classified into 7 items. Subsequently, the relationship between water requirement and 7 items were analyzed by evaluating the average water requirement in each condition to clarify the items influencing water requirement. From the analysis of the results, the water requirement of DC was determined to be 3.5 times of the TC. Furthermore, water requirement in DC and TC were influenced mainly by ponding depth and locational condition respectively.