The solubilizations of isomers of alkanols (butanol to octanol) in ionic micelles (sodium dodecyl sulfate and dodecyltrimethylammonium bromide) were measured by using polymer-coated piezoelectric gas sensors to discuss the effect of the molecular shape of alkanols on the solubilization in micelles. Good correlations were obtained both between the micelle/water partition coefficient (K) and the octanol/water partition coefficient of alkanols and between K and the molecular surface area of alkanols. This indicates that the solubilization in micelles depends only on the hydrophobicity of alkanols, because the micelles are too soft to recognize the molecular shape of alkanols.