Axis ratios of our sample of early-type galaxies as a function of stellar mass. The squares indicate median values, and the error bar of each square is 1σ of the median values from 200 bootstrap resampling. The axis ratio distribution of our sample shows that median axis ratios of the galaxies in the highest-density environment are ∼0.05 larger than those in low-density environments. This is probably due to the fact that early-type galaxies in the low-density environments have a bit more disk-like structure. However, environmental dependence of the axis ratios in our sample is small.