Japanese e-Commerce company Rakuten will buy out the ebook firm Kobo. The company says it wants to expand in the area of media downloads for consumers.

Rakuten already sells Panasonic’s digital reader Raboo in Japan. As per the deal, Rakuten will acquire Kobo for $315m in cash. Canada-based Kobo’s major shareholder is book retailer Indigo. However, Kobo will continue to operate out of Toronto, Ontario, its original location.

Kobo, which claims to have over 5 million users worldwide in October, has e-reading applications for Windows, Mac OS X, the iPad, iPhone, BlackBerry, and Android devices.

Rakuten joins Apple’s iPad, Amazon’s Kindle and Sony’s eBook Reader in the highly competitive e-reader market place. Rakuten executive Pierre Kosciusko-Morizet acknowledged that competition will be stiff.

The deal is expected to close in early 2012.