Walking behaviour of the humanoid robot depends on many parameters of body structure, in which, the foot structure is one of the most important factors since it directly interacts with the environment in the locomotion. In this paper, joint characteristics of the robot’s foot have been investigated for our further understanding of biped motion. These properties are stiffness and damping factor of spring of passive toe joints. The subject of this paper is a small humanoid robot named Kondo KHR-3HV belonging to the Kondo Kagaku company. The foot structure of the robot consists of a big toe and a tiptoe with passive joints using torsion spring. The effect of the structure property is collected and evaluated through dynamic simulation on Adams and analysis of variance (ANOVA).