* TSX ends up 100.72 points, or 0.5%, at 21,556.54

* Cannabis stocks are top five gainers on index

* Energy, materials sectors up 1.2%

Nov 8 (Reuters) - Canada's main stock index closed at a record for the third straight day on Monday, with cannabis stocks leading the charge on a report of a U.S. Republican-led marijuana legalization bill, and the Congressional passage of a $1 trillion U.S. infrastructure bill also lifting sentiment.

The Toronto Stock Exchange's S&P/TSX composite index closed up 100.72 points, or 0.5%, at 21,556.54, a record closing level.

"If there is some talk about (cannabis) legalization out of the U.S... any positive news on legalization and more usage," is a good thing, said Allan Small, senior investment adviser at Allan Small Financial Group with HollisWealth.

"The infrastructure bill, passing that is big... and the U.S. border opening up is a positive," he added.

The five biggest gainers on the Toronto benchmark were cannabis stocks Cronos Group, Tilray Inc , Canopy Growth , Aurora Cannabis and OrganiGram Holdings.

Cannabis news website Marijuana Moment reported https://www.marijuanamoment.net/republican-led-bill-to-legalize-and-tax-marijuana-emerges-as-alternative-to-democratic-measures Friday that a preliminary Republican-led bill to legalize and tax cannabis was being circulated, with a final version expected to be filed later this month.

The healthcare sector, which includes cannabis stocks, surged 8%.

The passage on Friday of a long-delayed $1 trillion infrastructure bill by the U.S. House of Representatives also boosted sentiment globally, with Canada expected to be among the beneficiaries of the resulting increase in demand for materials.

This also lifted oil prices globally on expectations that the infrastructure push will boost fuel demand.

U.S. crude prices were 1.2% higher at $82.22 a barrel.

The Canadian energy sector and the materials group, which includes precious and base metals miners and fertilizer companies, both also added 1.2%.

Gold futures rose 0.5% to $1,825.9 an ounce.

Sun Life Financial said it would resume dividend increases after the regulator lifted a pandemic-era moratorium on capital distributions. Its shares rose 1.1%. (Reporting by Nichola Saminather in Toronto; Editing by David Gregorio)