Abstract: A fall prevention device includes a shaft extending vertically through a multi-story building. A door is provided on each floor of the multi-story building. A cab is movably mounted in the shaft and includes a cab door. A movement device includes a power mechanism and first and second grid structures directly or indirectly connected to the power mechanism. The first and second grid structures are respectively fixed to top and bottom sides of the cab at locations adjacent to the cab door. Each of the first and second grid structure includes a plurality of rails spaced from each other in a width direction perpendicular to the vertical direction. The movement device further includes a first support device in a top end of the shaft and a second support device in a bottom end of the shaft. The first and second support devices respectively support the first and second grid structures.