A paper sheet handling apparatus , comprising: a paper sheet handling module to handle and convey a paper sheet; and a plurality of storage modules sequentially connected to the paper sheet handling module , wherein each of the storage modules comprises: a paper sheet storage cassette to store the paper sheet; a holding module holding the paper sheet storage cassette , wherein the holding module of each of the storage modules is detachably connected to the holding module of at least adjacent one of the storage modules ; and a conveyance assembly detachably connected to the holding module , wherein the paper sheet storage cassette and the paper sheet handling module are located at two opposite sides of the conveyance assembly respectively, and the conveyance assembly is adapted to convey the paper sheet between the paper sheet storage cassette and the paper sheet handling module , wherein the number of the storage modules is changeable for use with another paper sheet handling module , wherein each of the conveyance assemblies has two connecting ends opposite to each other, at least one of the connecting ends of each of the conveyance assemblies is adjacent to at least one of the connecting ends of at least another one of the conveyance assemblies , wherein all the conveyance assemblies have the same size, and the conveyance assemblies are each detachably connected to each other by the connecting ends . a paper sheet handling module to handle and convey a paper sheet; and a plurality of storage modules sequentially connected to the paper sheet handling module , wherein each of the storage modules comprises: a paper sheet storage cassette to store the paper sheet; a holding module holding the paper sheet storage cassette , wherein the holding module of each of the storage modules is detachably connected to the holding module of at least adjacent one of the storage modules ; and a conveyance assembly detachably connected to the holding module , wherein the paper sheet storage cassette and the paper sheet handling module are located at two opposite sides of the conveyance assembly respectively, and the conveyance assembly is adapted to convey the paper sheet between the paper sheet storage cassette and the paper sheet handling module , wherein the number of the storage modules is changeable for use with another paper sheet handling module , wherein each of the conveyance assemblies has two connecting ends opposite to each other, at least one of the connecting ends of each of the conveyance assemblies is adjacent to at least one of the connecting ends of at least another one of the conveyance assemblies , wherein all the conveyance assemblies have the same size, and the conveyance assemblies are each detachably connected to each other by the connecting ends . a paper sheet storage cassette to store the paper sheet; a holding module holding the paper sheet storage cassette , wherein the holding module of each of the storage modules is detachably connected to the holding module of at least adjacent one of the storage modules ; and a conveyance assembly detachably connected to the holding module , wherein the paper sheet storage cassette and the paper sheet handling module are located at two opposite sides of the conveyance assembly respectively, and the conveyance assembly is adapted to convey the paper sheet between the paper sheet storage cassette and the paper sheet handling module , wherein the number of the storage modules is changeable for use with another paper sheet handling module , wherein each of the conveyance assemblies has two connecting ends opposite to each other, at least one of the connecting ends of each of the conveyance assemblies is adjacent to at least one of the connecting ends of at least another one of the conveyance assemblies , wherein all the conveyance assemblies have the same size, and the conveyance assemblies are each detachably connected to each other by the connecting ends . <EOS>