To investigate the effect of different species of log on Shiitake (Lentinula edodes) fruit body development, we compared the number and quantity of fruit bodies, and bulk density and moisture content of the log between Quercus acutissima and Quercus crispula. The quantity of fruit bodies developed from Q. acutissima was 1.5 times greater than that from Q. crispula at 6 years after sowing. Q. acutissima developed fruit bodies two months later than Q. crispula. Each fruit body developed from Q. acutissima was heavier than that from Q. crispula at the early stage of development, while there was no difference in the dry weight over the 6-year period between the two species. The bulk density of logs before sowing was greater in Q. acutissima than in Q. crispula. The bulk densities of both species decreased with time, and they were 42% of the initial value for Q. acutissima and 26% for Q. crispula after 5 years of sowing. There was no significant difference in the moisture content of logs before sowing, while the increase in moisture content after sowing was greater in Q. crispula than in Q. acutissima.