A safety fence (11) installed on top of car (12) is formed of multiple holding members (18) that are installed upright on two side plates (15), (15) and back plate (16) of car (12), and columns (19), (19), (20) that are held in a freely vertically extendible manner in said holding members (18). Also, handrails (21), (21), (22) connect the upper ends of said columns, and at the same time, retraining members (23) are set to define the vertical position of the columns with respect to the holding members.