PURPOSE: To prevent a carrier from dropping when a track assembly is removed by mounting a lock member to be engaged with a carrier disposed at the open end of a connecting part of the assembly to other track assembly.

CONSTITUTION: A conveying track is divided into first and second track assemblies 30, which are detachably mounted on a device body of an IC handler, and a lock member 40 to be engaged with a carrier 14 disposed at the open end of a connecting part of other track assembly 30 is mounted at least at the one assembly 30 when it is removed from the body. When the assembly 30 is mounted on the body of the handler, the carrier 14 is movable on the connecting part of both the assemblies 30, while when the assembly 30 is removed from the body, the member 40 is operated. Thus, when the conveying track is replaced, it can prevent the carrier 14 from dropping.