Brewin has an expanding Financial Planning presence with income from Financial Planning growing rapidly in recent years. The company has more than 105 qualified Financial Planners and 129 Paraplanners and assistants.
The company last year acquired Bath-based Epoch Wealth Management LLP, an independent Financial Planning firm with 38 members of staff.
Mr Nicol decided to retire after eight years with the group, the company announced today.
He will step down on 13 June and will remain to hand over the ropes to Mr Beer until the end of July.
Mr Beer is currently responsible for Brewin Dolphin's intermediaries, charity, professional services and digital businesses.
Mr Beer has over 20 years of experience in financial services, previously working at National Australia Bank, Gerrard and Barclays.
He joined Brewin Dolphin in 2008 to open and run the Nottingham office. He subsequently assumed the role of regional director in the Midlands, before taking charge of the intermediaries' business in 2013 which has grown funds under management to over £14bn.
He joined the executive committee in 2016, with further responsibilities for research, investment governance and the development of investment solutions.
Mr Beer said: "I am delighted to be chosen to lead the business at this juncture and I look forward to continuing to build on David's achievements to drive the business through its next phase of development."
His appointment is subject to regulatory approval.
Mr Nicol said: "It has been a great privilege to lead Brewin Dolphin. After seven years as chief executive, and with the business well positioned for the future, I feel that now is the time for me to hand over to my successor. I am very pleased with the selection of Robin and I have every confidence in his future leadership."
Simon Miller, chairman, said: "On behalf of the Board, I would like to thank David for his outstanding contribution to Brewin Dolphin's success. Under his leadership, Brewin Dolphin has seen funds under management almost double from £26bn to £48.5bn. Our client proposition has deepened, we have invested in our office network, and both client satisfaction and employee engagement are at record levels."