The present invention can be applied in the technical field of medical instruments in neurosurgery, and provides a brain retractor device comprising: a flexible retracting component which comprises an expandable sacculus, a supporting tube, a connecting base, a lock mechanism lockable and matching with the connecting base, and a pressurizing device connector configured for expanding or retracting the expandable sacculus. A brain depressor is sheathed on a distal end of the flexible retractor component and enters an avulsed passageway avulsed by the flexible retractor component so as to make the avulsed passageway remain an avulsed status. In the brain retractor device, the lock mechanism is pushed into the connecting base, and the expandable sacculus is stretched and becomes slim, such that the length and the position of the expandable sacculus that enter the diseased region are controlled. Moreover, by injecting liquid into the pressurizing device connector, the expandable sacculus is expanded and when liquid is discharged, the expandable sacculus is retracted. By quantitatively controlling the amount of the liquid injected into the pressurizing device connector, the expanded diameter of the expandable sacculus is accurately controlled, and thus the size and the position of the avulsed passageway is accurately controlled, such that injury to brain tissue during the avulsing process can be reduced, the amount of bleeding in the surgery can be reduced, and cranial nerves can be protected to the maximum extent.
