Bourne has served as chairman of the board since May 2013, and he was director of the company prior to that.
The company delivered the news in a statement, and no reason was given for Bourne's decision.
The news comes the same day as a preliminary hearing begins in a fraud case involving SNC's contract to build the McGill University Health Centre's new superhospital.
SNC's former CEO Pierre Duhaime and another former top executive RiadhBen-Aissa are facing fraud, corruption and conspiracy charges in connection with an alleged $22.5 million bribe used to secure the contract.
Bourne has not been linked to the criminal case involving the former executives.