The U3-X - available for a test-run for reporters in Tokyo Thursday - was designed to be small, safe and unobtrusive enough to mingle with pedestrians, according to Honda Motor Co.
The single wheel on the U3-X - U stands for "unicycle" and "universal" - is made up of many tiny motor-controlled wheels, packed inside the bigger wheel, allowing the device to swerve in any direction.
It stands upright on its own. Sit on it as though it's a stool, and shift your weight to drive. The thing maintains its own balance as it scoots along at a speed of up to 6 kilometers (3.7 miles) per hour.
Honda President Takanobu Ito said the machine was still "a proposal," and the company has no sales plans, pricing or firm ideas on where or how it will be used.
Honda declined to give details of the U3-X's technology, but said it weighs less than 10 kilograms (22 pounds), runs on a full charge for an hour, and has a lithium-ion battery.
"I may want to use it in my home," Ito mused. "It'd be easier to get around so I might really use it if my legs grow weaker."
The U3-X takes a bit of getting used to. It was a bit too big for this 1.53 meter (five-foot) tall reporter, making it hard to sit on and control it well.
Although Honda said the machine is meant for the elderly, it's unclear whether they would be coordinated enough to control the device.
Honda makes the Asimo walking child-shaped robot as well as the Odyssey minivan and Accord sedan. The latest device uses some of the technology of balance and movement developed in the Asimo, Ito said.
Last year, Honda showed a gadget, which can support a wearer's bodyweight, made of mechanical frames attached to a pair of shoes. Honda said it may be used by auto workers.
Japanese rival Toyota Motor Corp. has shown machines that help people get around, including the Winglet, similar to the Segway, a scooter-like device that people ride standing up. Toyota also has displayed I-Real, a motorized armchair-on-wheels.
Japan is one of the most rapidly aging societies in the world, and concerns are growing about helping the elderly get around.
"Honda engineers are always thinking about people's dreams and wishes about mobility. We will continue to work hard to be a leader in that area," Ito said.