To provide a simple and inexpensive unmanned carrier capable of stably steering in both of forward and backward movements.

This carrier is provided at the center part of a vehicle body 2, has a drive wheel 16 supported in a freely traveling manner longitudinally in a traveling direction by a driving source, and reads recording of a guide line 17 provided on a traveling road surface 8 in advance to control steering of the traveling direction of the drive wheel 16. The carrier is provided with a driving unit 3 having a drive wheel control means 12 for a front and rear driving control, a front caster 4 supported in a traveling direction front part of the vehicle body 2 to be turnable around a vertical shaft together with a front traveling wheel 6 traveling in parallel to an axial direction, a rear caster 5 supported on a traveling direction rear part of the vehicle body 2 to be turnable round the vertical shaft together with a rear traveling wheel 7 traveling in parallel to the axle direction, and a steering switching means 9 to separate and move the rear caster 5 and the front traveling wheel 6 from the traveling road surface 8 at the same time when grounding the front caster 4 and the rear traveling wheel 7 on the traveling road surface 8 when traveling the vehicle body 2 in one direction of the traveling direction by the driving unit 3.

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