To provide a hose coming-off prevention device for a forklift truck for adjusting a variation in dimension generated for the each forklift truck.

The hose coming-off prevention device is provided with a rotation stop plate 12 which can abut on a lower part of an upper stay 11 projectingly provided in right and left masts 1, and a bar fixing plate 13 which can vertically slid with respect to the rotation stop plate 12 and is fixedly provided with a hose coming-off prevention bar 14 having a function of preventing a hose 8 hung on a pulley bracket 7 from coming off. Further in the device, the rotation stop plate 12 and the bar fixing plate 13 are fixed to an axis of the pulley bracket 7 provided to an upper part of the mast 1 with a bolt, and the hole part 16 formed in the rotation stop plate 12 for penetration of the bolt 15 is made in a vertically long hole shape.