As shown in Test Examples 2-2 to 2-4, the solidification point and the hardness can be increased by adding 1 to 2% of trimethylglycine while maintaining the solubility by rubbing and the foaming power. In addition, even when trimethylgly cine is increased to 4 to 5%, the function of soap itself is not hindered in particular. However, the aesthetic appearance as
transparent soap is affected with crystallization.