The Opposition leader is travelling to the Hampshire town where the Lib Dems are engaged in a fierce battle to prevent their Tory coalition partners snatching the seat.
Labour is hoping for a good showing in the contest sparked by the resignation in disgrace of ex-cabinet minister Chris Huhne after he admitted dodging a speeding penalty.
But despite recruiting best-selling author and satirist John O'Farrell as its candidate, insiders acknowledge it has no realistic chance of winning on February 28.
Mr Miliband will use his visit in a bid to capitalise on his surprise announcement yesterday that Labour favoured reviving the 10p income tax rate.
More top news
The major party leaders' campaigns for the General Election will remain suspended on Wednesday following the Manchester terror attack.
Thousands of people have donated to help the families of the victims - as well as a homeless man who came to their aid.
Some children, particularly those who have been more directly affected, may show symptoms of stress and trauma.