The theory of degrowth within ecological economics is divided into two groups: N. Georgescu-Roegen, S. Latouche and K. E. Bullding, H. E. Daly, T. Jackson. Although in the former, this theory results in the denial of all growth, in the latter, it does not. This difference seems to be a difference in interpretation of the laws of thermodynamics, but behind it lies a difference in preanalytic visions. Bullding, Daly and Jackson believe that the sustainability of human society can be secured through balanced growth or a steady state economy, but Georgescu-Roegen and Latouche do not share this belief. This difference in belief or vision has resulted in different theories of degrowth, and I compare the two degrowth theories in this article.