The hosts are big favourites to win the tour, and some have even predicted a whitewash in their favour due to off-field troubles endured by the Aussies over the past month.
However, Broad insists that England will not be taking Australia lightly and are ready for a battle, starting on Wednesday at Trent Bridge.
"It's the first time in an Ashes series we've gone in as favourites that's for sure, certainly in my lifetime but it's not something that worries us," said Broad.
"We know Australia are tough competitors, I think anyone who's writing England are big favourites and will win the series etc, have either not played against Australians or forgotten what it's like to have played against Australians.
"We know we're going to be in for a battle, and to be honest what happens within the four walls of the changing room is all that really matters. As long as the 11 guys who step on the field on Wednesday are mentally and physically in the right place, which we are at the moment, that's all that matters."
England have won the previous two Ashes series.