Bell has been with Mercedes since April 2011 but outlined his desire to leave after the 2014 campaign in December in order to focus on challenges away from the team.
Mercedes revealed that they would not be replacing Bell with another technical director, instead handing his duties to current technical executive director Paddy Lowe.
"Bob resigned his position in December 2013 and will leave the team at the end of November 2014, with the intention of pursuing new challenges outside the company," read a team statement.
"He has held the position of technical director since April 2011. Moving forward, the team will streamline its technical organisation and executive director (technical) Paddy Lowe will assume the responsibilities previously held by Bob.
"The role of technical director will not be replaced."
Bell, 56, has been involved in motor racing since 1982, previously working with McLaren, Benetton, Jordan and Renault before his stint with Mercedes.