"We do not have plans to develop a successor Reader model at this time," the Japanese firm told the BBC.
The PRS-T3 was the last version made and will exist as long as supplies remain in Europe.
Earlier this year, Sony pulled out of selling e-books and directed its users in the US and Europe to the e-bookstore of rival Kobo.
North American customers using Sony Readers have been directed to buy books from Kobo since February this year, and European and Australian customers since May, a Sony spokeswoman said.
But users in Japan, Sony's home country, can continue to still get its line of Readers and access Sony's Reader Store.
The news was first reported by German site Lesen.
The dominance of Amazon's range of Kindles and the growing smartphone, tablet and so-called phablet market have made it hard for Sony's suite of e-readers and rivals like Nook to carve out a niche for themselves. According to The Bookseller, Amazon has around 90% of the dedicated e-reader market in the UK.
Canadian firm Kobo was bought by Japanese e-commerce company Rakuten, which is looking to grow its business globally in a bid to challenge Amazon.
The global market in dedicated e-readers peaked in 2011 with 23 million devices sold, but is expected to fall to 10 million by 2017 as phones and tablets eat into the overall market, according to the research consultancy Gartner.
Still, the sale of printed books will be outstripped by e-books by 2018, a report by Pricewaterhouse Coopers suggested.
Sony has given up selling its line of Reader devices for e-books after failing to find a big enough market.