PURPOSE: To dispence with an upsized in/out device by arranging the center of the width in the right-to-left direction of a cab constitution consisting of a cab and a cab side ramp so as to be coincident with the center of the body.

CONSTITUTION: A cab 30 which is used in the maintenance and inspection or in an emergency is elevatably provided on the outside of a pillar 12. The cab 30 is elevatably held to a cab guide rail 19 which is mounted on the outside of the pillar 12 through a plurality of rollers mounted on brackets 32, and the cab 30 is arranged so that the cab center 30A in the right-to-left direction may be deviated to one side relative to the center 14A of a traveling body by the specified distance L. A cab side ramp 34 is continuously provided before a door body 33 in an integrated manner with a bottom plate 35 of the body 31, and a carriage side ramp 38 is continuously arranged opposite thereto. The center in the right-to-left direction of the cab side constitution consisting of the cab 30 and the cab side ramp 34 is coincident with the center 14A of the body.