A quick brake adjust knob (2), which is disposed on an axle (3) of a fishing reel (1), includes a base disc (10), a passive member (20), an elastic member (30), a threaded member (40), an active member (50), and a panel disc (60). The passive member (20) has a first arc slope (26) gradually approaching the outside of the knob (2) from a first staring end (261) thereof to a first terminal end (263) thereof and C-shaped with a breach where a first recess (265) is provided. The active member (50) has a first protrusion (54) abutted against the first arc slope (26) or accommodated in the first recess (265). The panel disc (60) is fixed to the active member (50) and rotatable relative to the base disc (10). The periphery of the panel disc (60) is joined with the periphery of the base disc (10). Therefore, the quick brake adjust knob (2) can quickly and precisely control the resistance of the fishing reel (1) to stretch out the fishing wire.
