The spatio-temporal characteristics of drought occurrences in East Asia (105-150°E, 20-50°N) have been investigated using Effective Drought Index (EDI; Byun and Wilhite, 1999) from 1962 to 2004. First, East Asia can be divided into six drought divisions: (D1) South China, (D2) Lower region of the Yangtze River, South Korea, and Central/South Japan, (D3) Central China and North Korea, (D4) Northwest China and middle region of the Yangtze River, (D5) North China, and (D6) Northeast China and North Japan. Second, a drought map has been constructed using time series of daily mean EDI of each drought division. The following details were confirmed by a drought map: (1) The drought durations of all divisions were represented by bimodal distribution, which has two peaks before and after 200 days. (2) The onset dates of droughts of each division have different seasonality (3) The droughts have a different time-scale depending on the onset season.