LINCOLN, Neb. (AP) _ The pupils in Nancy Hinrichs' fourth-grade class at Holmes School were angry when they saw a calendar that showed the Campbell Soup Kids making a derogatory reference to American Indians.

As a writing assignment, the 26 pupils in the class wrote letters to the company objecting to the use of the term ''honest injun'' in the Campbell Kids 1985 Salute to America calendar. And, to their surprise, each received a personal apology from the company's public relations chief.

The calendar, which Ms. Hinrichs had ordered for use in the classroom, features a different section of the country each month and a poem about Campbell's Soup.

Ms. Hinrichs said the class had been discussing the importance of equity in the treatment of all groups of people when she turned to the page for February and asked, ''What do you think about this verse?''

The picture showed the red-cheeked Campbell Kids standing in front of Mount Rushmore, with this poem:

''Honest injun soup is great,

''In lots of famous places,

''It's even sure to bring a smile

''To Mount Rushmore's stoney faces.''

The pupils replied that the verse ''didn't sound right,'' Ms. Hinrichs said. They talked about how the word ''injun'' is derogatory, and ''just like a swear word against a total race,'' she said.

Every pupil received a personal reply from James H. Moran, public relations manager for the company in Camden, N.J.

Moran wrote something different to each pupil.

For example, to Danny Williams he wrote: ''You are absolutely right. We shouldn't have used the words 'Honest Injun.' And you're right also in saying that we don't deserve to sell that much soup if we use terms like that.''

To Sean Bovey, Moran responded: ''What can I say? We were very wrong to use that phrase about Indians. The person who wrote it just thought he was being cute. He didn't realize that he might be insulting a proud segment of our population.''

In one letter, Moran noted that Indians are employed in Campbell's offices and plants, including three plants in Nebraska.

He assured the Holmes pupils that it wouldn't happen again.

Ms. Hinrichs said writing letters to real people is a frequent assignment in her class, but she said that pupils have never before received such an overwhelming response.

''We talked about why a big business would be more likely to respond to complaints like this,'' she said, adding that it led to a discussion of consumer economics as well as equity.