Honda Motor Co., which expects half of the vehicles it sells in Japan this year to be minicars, will unveil its first mini sports car since 1996 amid booming demand for more fuel-efficient, cheaper autos.

The S660 concept mini sports car will be introduced at the Tokyo Motor Show next month and begin selling next year, Honda said. The two-seater will be a convertible, Ryo Sugiura, its exterior designer, told reporters.

The S660 will be one of the six minicars Honda plans to introduce by 2015 to challenge Daihatsu Motor Co. and Suzuki Motor Corp., the leaders in a category that accounts for about 40 percent of all sales of new cars in Japan.