There is provided a workpiece supply/conveyance device that can remove a workpiece from a spindle and supply another workpiece to the spindle smoothly and in a short time. A workpiece holding section of one of a plurality of arms includes an unmachined workpiece holding section 29 for holding an unmachined workpiece and a machined workpiece holding section 21 for holding a machined workpiece. When the plurality of arms are rotated in one direction, each of the arms is moved to an unmachined workpiece loading position III at which the unmachined workpiece holding section receives the unmachined workpiece, a standby position IV in a standby state while holding the unmachined workpiece to be next machined in the unmachined workpiece holding section, a workpiece delivery/reception position I at which the workpiece is delivered and received among a workpiece machining apparatus, the unmachined workpiece holding section and the machined workpiece holding section, and a machined workpiece unloading position II at which the machined workpiece held in the machined workpiece holding section is unloaded.