Workpiece holding jig for vibratory barreling, and vibratory barreling method

A workpiece holding jig is a vibratory barreling jig which holds a flat workpiece when the workpiece is polished by a vibratory barreling device using polishing media. The workpiece holding jig includes disk-shaped guard members and each having an outer shape larger than the workpiece and disposed so as to face each other and a holding member holding the workpiece inside a housing space so that the entire workpiece is located inside the columnar housing space. The guard members and are respectively provided with window portions communicating with the housing space. The window portions and the annular imaginary curved surface extending to connect the peripheral edges of the guard members are configured to allow the polishing media to pass between the inside and outside of the housing space.