Many quadrupeds change their gait from a walk to a trot, and finally, to a gallop depending on the locomotion speed. These locomotion patterns are generated via the coordination between limbs, i.e., interlimb coordination, and are partly controlled by an intraspinal neural network called the central pattern generator (CPG). However, a proper understanding of interlimb coordination mechanism remains elusive. Here, we demonstrate the gait transition experiments with a simple quadruped robot, which limbs are coordinated by an unconventional CPG model that we previously proposed. By only changing a parameter of locomotion speed, our robot exhibited spontaneous gait transition from a walk to a trot, and then to a bound, even in the absence of direct neural interaction between the oscillators of the CPG. Very interestingly, we found a canter -an asymmetric, three-beat gait- in the transition from a trot to a bound. In this paper, we discuss the generation mechanism of canter gait.