The abundance of earthworm in the agro-ecosystem was assessed on the basis of 1,846 individuals collected from May to October 2006. Material was found from litter layers in soils by hand sorting and digging. They encompassed 3 families, 5 genera, and 15 species. Species composition and abundance were as follows: Amynthas agrestis 20.9%, Amynthas koreanus 20.3%, Amynthas heteropodus 15.4%, Amynthas sp. 8.7%, Drawida japonica 8.0%, Eisenia fetida 7.2%, Amynthas hilgendorfi 7.0%, Bimastos parvus 3.2%, Amynthas hupeiensis 2.5%, Aporrectodea caliginosa 1.8%, Amynthas corticis 1.8%, Aporrectodea tuberculata 1.3%, Eisenia andrei 1.2%, Amynthas sp. 20.4%, and Amynthas sp. 10.3%. Of 1,046 individuals, the A. agrestis, A. koreanus, and A. heteropodus were the most numerous members with abundance of 56.7%. Disc-shaped male pore region is useful for classification of Amynthas, and in the survey, we collected two new species with male discs from lettuce cultivated region, Amynthas sp. 1 Amynthas sp. 2. The clitellate vs. aclitellate ratio of the earthworm was approximately 1.25:1.0.