A rollator includes a support frame assembly, a handgrip unit pivotable relative to the support frame assembly between depressed and non-depressed positions, at least three wheels mounted pivotally to a bottom portion of the support frame assembly, and at least one braking device including a brake wire unit connected to the handgrip unit, and a brake fixed to the support frame assembly at a location proximate to one of the wheels and connected to the brake wire unit. The brake includes a casing, a stop member, and a gear connected coaxially to one of the wheels. The stop member is movable between free and braking positions where the stop member is spaced apart from and is engaged with the gear, respectively.