In welfare facilities, although wheelchairs are commonly used for transferring patients, there are many cases in which patients are transferred while lying on beds because it is burdensome for caregivers to move a patient from a bed to a wheelchair. However, the task of moving a bed with a patient lying on it is still physically burdensome for caregivers. Hence in this study, we developed a power-assist omni-directional mobile bed to reduce the burden associated with this task. This paper reports a novel prototype of the omnidirectional power-assist bed and describes the prototype’s design, mechanism and control-system configuration. In addition, we report on experiments that were conducted to verify the effectiveness and usefulness of the omni-directional mobile bed, as well as the adaptability of the omni-directional power-assist system.