Robert Pontzer, 46, the eastern regional manager of the Astronics Division of Lear Siegler, Inc., died of cancer Thursday at Fairfax Hospital. He lived in Vienna.

Mr. Pontzer, who was born in Ridgway, Pa., earned a bachelor's degree at Georgetown University in 1956. After serving in the Marine Corps, he returned to the Washington area and began a career in the space industry and related fields.

He began as the personnel supervisor for Melpar, Inc. He later was the Washington sales representative for a number of companies, including Airtronics, Orbit, Laboratory for Electronics and Teledyne Ryan. In 1972, he joined the Astronics Division of Lear Siegler as its eastern regional manager. He remained in that job until his death.

Mr. Pontzer was a member of the Air Force Association, the Association of the U.S. Army, the Association for Unmanned Vehicles, the American Defense Preparedness Association, the Old Crows, a social and professional organization whose members are concerned with electronic weaponry, the Navy League, the National Rifle Association and the National Aviation Club.

Survivors include his wife, the former Marion Hayward, of Vienna; three sons, Robert (Fritz) of Bakersfield, Calif., and John and James, both of Vienna; four daughters, Stephanie, Suzanne, Leila and Kristine, all of Vienna; his mother, Bertha Pontzer of Ridgway; two brothers, Dr. Peter of Altoona, Pa., and John of Ridgway, and two sisters, Dione Peckham of St. Louis, Mo., and Patricia Lanese of Ridgway.

The family suggests that expressions of sympathy be in the form of contributions in Mr. Pontzer's memory to the American Cancer Society, P.O. Box 699, Vienna, Va., 22180.