To provide a horizontal detachable device for a baggage box in a detachable vehicle capable of confirming a position adjustment of a car body and a baggage box just at a neighborhood when the baggage box is loaded on the car body and smoothly carrying out a loading work of the baggage box.

In the horizontal detachable device 2 for a baggage box in a detachable vehicle 1, the baggage box N detachably loaded on the car body 10 is separated from the car body and is supported by a support leg 3 and the car body and the baggage box are relatively moved to remove the baggage box to an approximately horizontal direction against the car body. The device 2 is provided with a first arm 21 forwardly inclinable against the car body and capable of shaking the head to a right/left direction; and a second arm 24 slidable in a forward/rearward direction of the car body against the first arm. When the baggage box is unloaded, the baggage box is attached/detached against the second arm by expanding/shrinking the support leg in the state that the first arm is inclined and the second arm is slid to a rear part of the car body.