To prevent punched slug from dropping on a worm wheel formed on the outer circumference of an index lower holder without changing the outer shape and the function of the holder itself.

This auto-index die device is composed by attaching an index lower holder formed with a worm wheel 13 on the outer circumference to an attaching hole of a lower die supporting member and attaching a die holder 57 arranging plural numbers of index dies 63 on the circumference onto this index lower holder so as not to rotate. In this case, a stepped part 93 is installed on the upper part of the index lower holder in the up and down directions by making an upper holder part 89 and a lower holder part 91 being larger than the upper holder part as one body, a projection part 79T projecting to the upper part of a 2nd spacer is engaged to this stepped part, and a 1st die spacer 81 is installed attachable and detachable on the 2nd die spacer 79.