Dubbed "Pepper," the robot will go on sale to the general public next year for 198,000 yen, or around $1,900.
Read MoreUS defense robots in 2039: Attack of the clones?
The company also plans to develop a household robot that can care for the elderly, according to the Nikkei newspaper, which would put it in competition with Honda Motor's personal "Asimo" robot.
Japan's robotics market is forecast to hit nearly $35 billion by 2020, according to a 2013 trade ministry report.
SoftBank also controls 34 percent of Alibaba, the Chinese e-commerce company that is expected to make the largest-ever technology debut on New York's stock exchange later this year. With Alibaba's value estimated around $150 to $250 billion, SoftBank's stake could easily top the $50 billion mark.
Read MoreFive things to know about Alibaba
"Son has done an excellent job, you can't ask for more from a Japanese CEO. Apart from invading the U.S. market, Son could very well take over the world," said Ben Collett, head of Asian Equities at Sunrise Brokers.