We focus on the inter-limb coordination derived by an ingenious trunk for the realization of various locomotion of multi-legs robot. In this paper, we design a bran-new trunk mechanism in which is equipped with an actuator and build 6-legs robots with passive limbs with the trunk. Through walking experiments with the developed robot, we analysis its locomotion. In addition, we focus on the effect of the physical characteristics of the robot. We also analyze the effect of the physical characteristics on the inter-limb coordination.