To simplify and to realize the multi-function of a hemming system in which a work on a lower die positioned on a working stage side is hemmed by a hemming unit of a robot arm.

In the hemming system in which a peripheral edge part of the work 1 positioned on and held by a lower die 10 on the working stage 20 side is hemmed by a hemming unit 32 of the robot arm 30, a conduction detection device 37 to detect presence/absence of the conduction by bringing the hemming unit 32 into contact with a predetermined part of the work 1 by the robot arm 30 to perform conduction therebetween is disposed on a robot control system 35 to drive the robot arm 30, presence/absence of the work 1 on the lower die 10 is checked by the conduction detection device 37 before the hemming is performed, and the kind of the work 1 is checked by the conduction detection device 37 by bringing the hemming unit 32 into contact with a kind setting display unit 60 installed on the working stage 20 side as necessary.