Meanwhile, 25 percent support Republican Donald Trump, a former president, according to the survey by pollster CBOS.
Twelve percent expressed no preference for either contender, and another 12 percent were undecided.
When asked who they believe will actually win the election, 40 percent of respondents predicted a Harris victory, while 37 percent identified Trump as the likely winner.
Kamala Harris and Donald Trump. Photos: PAP/EPA/WILL OLIVER/ERIK S. LESSER
The survey was carried out from October 21 to 24 on a sample of 1,000 adult respondents in Poland, state news agency PAP reported.
A Reuters/Ipsos poll on Tuesday showed that Harris, the current vice president, leads Trump among registered US voters, with 44 percent support to Trump's 43 percent, the Reuters news agency reported.
It said Harris has led Trump in every Reuters/Ipsos poll since entering the race in July, though her advantage has steadily narrowed since late September.
American voters will go to the polls on November 5 to select their next president.
(gs)
Source: PAP, Reuters