Burrowing and disposal of cow dung pad by Onthophagus lenzii Harold, a predominant paracopric dung beetle in southwestern Japan, depleted moisture content of cow dung. Soil was mixed into the residual cow dung and dung balls, and diluted organic matter in these samples. This activity caused a significant decrease in loss on ignition, total carbon and total nitrogen contents of the residual cow dung and dung balls. A part of cow dung was disturbed and was buried into the underlying soil, in particular, into the upper layer (0-2cm) of the soil. Total carbon and total nitrogen contents of the upper layer of the underlying soil, thus, simultaneously increased while total nitrogen content alone increased in control so. Microbial numbers in residual dung and dung balls essentially reduced along with the action of the beetles. However, there was not the significant difference among the microbial numbers in the samples when the numbers were compared on the basis of 19 of total carbon. The action of the beetles changed the microenvironment being suitable for fungal growth rather than bacterial growth. Microorganisms increased in the upper layer of the underlying soil. Bacteria and actinomycetes in soil were more dependent on the beetle activity than fungi.