To provide a workpiece conveying/guiding mechanism and a method of guiding the workpiece, wherein the workpiece can be guided even when the width of the workpiece is reduced during conveying of the workpiece.

The workpiece conveying/guiding mechanism for guiding the width direction of a hoop material 20 when conveying the hoop material 20, is provided with a workpiece guide 30 for guiding the width direction of the hoop material 20, a slide cam 31 having an inclined cam face 31a which is connected to the workpiece guide 30, and a spring 34 for energizing the workpiece guide 30 in the direction of approaching the workpiece guide 30. The workpiece guide 30 is driven in the direction of separating from the workpiece guide 30 by pressing the inclined cam face 31a.