A reel brake device in a recording and reproducing apparatus is operated by a tape loading mechanism. A cam portion is formed on any one side of at least one of a pair of loading gears employed for driving a pair of tape guide units which draw a tape from the cassette. The reel brake for braking the reels includes a friction member for braking the supply reel table and an operating portion which comes into contact with a cam surface and a cam protrusion surface of the cam portion selectively so that it may be driven. Under a tape unloading condition, the reel brake performs braking or releasing operation of the reels as the loading gear rotates in a predetermined direction. Driving of the reel brake by the existing loading gear without using any separate driving element, makes it possible to maintain the brake stroke, enhance the accuracy in operation, and reduce the number of elements constituting the supply reel brake device.