To provide a duplicating form group for preventing alteration, formed by providing a large number of duplicating forms effective in preventing alteration.

The duplicating form group for preventing alteration is formed by providing a large number of duplicating forms 10 each formed by binding an upper form 11 and a lower form 12 separably. The front face of each upper form 11 is provided with an information entry part, and the front face of each lower form 12 is provided with an information duplicating part corresponding to the information entry part. The rear face of each upper form 11 is provided with color couplers 21, 22 corresponding to at least the information entry part, and the front face of each lower form 12 is provided with a developer 23 corresponding to at least the information duplicating part. The color couplers 21, 22 have, in part, portions colored in different colors from the other part, and the respective duplicating forms 10 are grouped by the portions colored in different colors and made different group by group.