Mobile carrier KDDI Corp. will wholly acquire Aeon Corp., the nation's second-largest English conversation school operator, in January in a step to expand its business into the education field.

KDDI said Wednesday it will acquire all shares in Aeon held by its founding family members for an undisclosed price on around Jan. 22, to make the Okayama Prefecture-based company a wholly owned subsidiary.

The move represents KDDI's latest efforts to diversify its business in the face of sluggish growth of its mainstay telecommunication operations in graying Japan. KDDI has already made inroads into the financial and energy industries.

Aeon has also found benefits in the deal as the company seeks to increase its number of students by expanding online lessons and other services utilizing information and technology, which have become popular in recent years.

An Aeon spokesperson said it is not a rescue-type acquisition, noting that the company has been seeing steady growth in its sales and profits.

Operating about 350 schools nationwide, mainly for English conversation practice, Aeon has amounted sales of ¥27.3 billion ($244 million) in 2016 on a consolidated basis — making it the second-largest operator by sales value after industry leader ECC Corp.