SoftBank Chief Executive Masayoshi Son will announce the plan at a news conference on Thursday at 1:00 p.m. local time (0400 GMT), the people said. They declined to be named as the matter remained confidential.
Softbank will use technologies developed by French robotics company Aldebaran, in which it took a stake in 2012, the people added.
The Nikkei business daily said production of the robots would be outsourced to Taiwanese electronics manufacturer Hon Hai Precision Industry Co Ltd. SoftBank and Hon Hai declined to comment.
The people said it was not immediately clear when the robots would be ready, but the Nikkei said Softbank would put robots in some of its stores this summer and eventually develop a household robot that could provide nursing care for the elderly.
Japan's population is one of the most rapidly ageing in the world and the government hopes companies can offset a decline in the labour force by utilising robotics.
Japan's overall robotics market was worth about 860 billion yen ($8.38 billion) in 2012 and is forecast to more than triple in value to 2.85 trillion yen by 2020, according to a trade ministry report last year.
A draft government growth strategy obtained by Reuters calls for a "robotic revolution" that would increase the use of robots in agriculture 20-fold and double manufacturing use.
A number of Japanese technology manufacturers are targeting robotics for growth. Panasonic Corp and robotics research subsidiary ActiveLink Co Ltd this week showcased robotic suits and vests to assist in arduous manual tasks such as carrying heavy loads or picking fruit from trees.
© Thomson Reuters 2014