Wheelchairs are welfare support devices that are indispensable for the lives of people with disabilities, including the elderly who have lower limbs problems, and contribute significantly to the QOL of users. Manual wheelchairs can move in the front-back direction and turn, but cannot move in lateral or diagonal directions. Therefore, it is difficult to operate them in a narrow space. On the other hand, many studies on omnidirectional movement mechanisms have been studied so far, but in order to utilize these functions, it is essential to transfer from a manual wheelchair a person is using. In order to solve this problem, we have developed a removable omnidirectional automotive mechanism that can be attached to the wheelchair and detached from it instead of changing wheelchairs. In this paper, we show the configuration of the proposed omnidirectional movement mechanism and the verification of the omnidirectional movement accuracy of the prototype.