A brake mechanism for a walker, essentially comprised of a brake disk with toothed peripheral is provided on the side of the wheel, a brake base allows relative displacement, and toothed section on the inner side of the brake base, wherein, said brake base as pushed by an elastic member holds with its toothed section against the toothed peripheral of the brake disk to brake the wheel in normal status, a handle is used to manipulate a brake cable to pull the brake base so to release the brake; furthermore, a turning block in the shape of a turntable is provided to accommodate the same brake cable connecting both brake handle, the turning block is further connected to another two brake cables to synchronously activate the brake mechanisms for the RH and the LH wheels; by pulling either brake handle, the synchronous release or brake of both brake mechanism can be achieved while allowing a 2-step brake.