Nathra Nader, a Lebanese immigrant who became a restaurant and bakery owner in Winsted, Conn., and who was the father of Ralph Nader, the consumer advocate, died on Sunday at his home in Winsted. He was 98 years old.

He died of heart failure, his family said.

Mr. Nader came to the United States in 1912 at the age of 19. He worked at a variety of jobs until he started his own grocery store in Danbury, Conn., later moving to Winsted to open what became the town's main restaurant and informal gathering place.

A strong advocate of civic training for schoolchildren, he frequently spoke out on public issues. In the mid-1970's he filed a lawsuit seeking to invalidate a ban on participation by independent voters in party primary elections, and in 1977 he held a march in Winsted to protest a Congressional salary increase.

In addition to his son, who lives in Washington, Mr. Nader is survived by his wife, the former Rose Bouziane; two daughters, Claire, of Winsted, and Laura Milleron of Berkeley, Calif, and three grandchildren.