[Purpose] The purpose of this research was to investigate the occurrence and mechanism of floating toe from the viewpoint of the structure of foot arch.[Subjects and Methods] The subjects were 65 adult females who had no history of orthopedic disease. Subjects stood on a pedoscope and we took images of the soles. According to a floating-toe score which we created, we allocated subjects to a normal group and a floating-toe group using the obtained images. We measured the arch height percentage in the sitting position and standing position in the normal group and floating-toe group and found the difference of arch height percentage (value obtained by subtracting the arch height percentage in the standing position from that in the sitting position). Results of the measurements were compared between the two groups. [Results] Among 65 cases, 23 were allocated to the normal group and 18 were allocated to the floating-toe group. There was no significant difference between the two groups for the arch height percentage in the sitting and standing positions. The difference of arch height percentage in the floating-toe group was significantly smaller. [Conclusion] We presume that there are two types of foot - the type in which the arch rises and the type in which the arch lowers in the floating toe, and lifestyle, footwear and other factors are involved.