A temporary storage apparatus for temporarily storing carriers between overhead travelling vehicles and a load port located in front of an equipment, the temporary storage apparatus comprising: a local vehicle provided with a hoist configured to raise and lower a carrier; a travelling rail for the local vehicle passing over the load port and provided below a travelling path of the overhead travelling vehicles; and a slidable buffer comprising: a cell configured to support a carrier thereon; and a guide mechanism configured to support and to slide the cell between an advanced position under the travelling rail and a backwards position laterally separated from the travelling rail, wherein the guide mechanism is configured to move between an active position laterally protruding from the travelling rail, and a retracted position laterally less protruding from the travelling rail by a shorter length than the active position and allowing an overhead travelling vehicle to transfer a carrier to the load port, wherein the travelling rail extends along a front face of the equipment to a waiting position for the local vehicle, and wherein the local vehicle is configured to wait at the waiting position when no work is allocated to the local vehicle, the temporary storage apparatus further comprising: a frame; wherein the guide mechanism is attached to the frame in a rotatable manner about an axis parallel to the travelling rail together with the cell, and wherein the guide mechanism and the cell are separated from the advanced position and the backwards position under the travelling rail at the retracted position. a local vehicle provided with a hoist configured to raise and lower a carrier; a travelling rail for the local vehicle passing over the load port and provided below a travelling path of the overhead travelling vehicles; and a slidable buffer comprising: a cell configured to support a carrier thereon; and a guide mechanism configured to support and to slide the cell between an advanced position under the travelling rail and a backwards position laterally separated from the travelling rail, a cell configured to support a carrier thereon; and a guide mechanism configured to support and to slide the cell between an advanced position under the travelling rail and a backwards position laterally separated from the travelling rail, wherein the guide mechanism is configured to move between an active position laterally protruding from the travelling rail, and a retracted position laterally less protruding from the travelling rail by a shorter length than the active position and allowing an overhead travelling vehicle to transfer a carrier to the load port, wherein the travelling rail extends along a front face of the equipment to a waiting position for the local vehicle, and wherein the local vehicle is configured to wait at the waiting position when no work is allocated to the local vehicle, the temporary storage apparatus further comprising: a frame; wherein the guide mechanism is attached to the frame in a rotatable manner about an axis parallel to the travelling rail together with the cell, and wherein the guide mechanism and the cell are separated from the advanced position and the backwards position under the travelling rail at the retracted position. a frame; wherein the guide mechanism is attached to the frame in a rotatable manner about an axis parallel to the travelling rail together with the cell, and wherein the guide mechanism and the cell are separated from the advanced position and the backwards position under the travelling rail at the retracted position.