In this paper, we propose a shoes-attachment system to attach and release wearable mobility by simple action of one leg. This attachment does not need a purpose-built shoes and the operation by hands. To embody this idea, a slide mechanism and newly proposed lock mechanism are used. The lock mechanism switches its lock or release mode by the speed of leg motion. The attach and release action are very simple. To attach to the shoe, a person needs to only step on the attachment. In the period of using the mobility, the attachment locks the shoes to the mobility. To release shoe from the attachment, the person needs to raise his feet slowly. In this report, we introduce the mechanism and report the verification of this mechanism.