A Prince George's County fifth grade pupil has been suspended and faces possible expulsion from school for bringing a loaded, automatic handgun to class, where his principal found it stored in a pencil box in his desk, police and school system officials said yesterday.

The 10-year-old boy, who was not identified because of his age, told police he took the gun to Kenilworth Elementary School in Bowie to protect himself from Kenilworth pupils who had assaulted him after a bus ride to his Capitol Heights home, officials said.

The incident at Kenilworth, a school of 622 pupils in a middle-class residential neighborhood, surprised officials, particularly because of the pupil's age. "If he's not the youngest, he's probably one of the youngest" pupils to take a gun to school, said Peter D. Blauvelt, chief of security services.

The pupil was suspended from the school pending the hearing on his expulsion, scheduled to take place Monday before school officials, a spokesman said. The boy was arrested Jan. 23 for possessing a gun and was released to his parents' custody, according to police. The case has been referred to the county's juvenile court.

Police said the gun belonged to a family member.

"I was quite shocked," said Principal John W. O'Donnell. " . . . I would like to think it was simply something he did not realize the consequences of."

County school officials, who enforce the strictest expulsion policy in the area to discourage possession of weapons on campus, said handguns are rarely found at elementary schools.

"We take an extremely dim view of any person, regardless of age, bringing a handgun to school," said school spokesman Brian J. Porter. "The child may suffer the consequence that may belong at the hands of his guardians for having what appears to be open access to a firearm within his own house."

Prince George's school regulations call for expulsion in most cases for drug distribution or carrying a weapon on campus.

School regulations make no provision for the education of a child who is expelled. School officials also have the options of suspending a student long term or transferring him or her to another school.

Last school year, 196 students were expelled from county schools, 143 for possession of a weapon.

Reports show that officials found 182 weapons at county schools last year. At elementary schools, they discovered seven weapons, including six knives, one "starter" pistol normally used at athletic events and one unspecified weapon.

Police said that in the most recent case, the weapon was discovered in the boy's desk after a pupil informed the teacher that the boy had brought a gun.

O'Donnell said the boy's teacher had been told about a gun by another pupil after the boy had shown a gun to several children at a bus stop that morning.

The boy is one of about 100 pupils who are bused from largely low-income Capitol Heights to the Bowie school, which he has attended since kindergarten. He told police that two pupils who ride the same bus had threatened him and assaulted him after school one day, officials said.

O'Donnell said he had ordered those pupils off the bus for a week because they had disobeyed the bus driver's order not to chase the boy after he left the bus.

The principal said he and a teacher searched the boy's desk during recess and found a gun in a cigar-type box that pupils use to store pencils and pens.

"I wasn't about to touch it," said O'Donnell, who said he carried the gun in the pencil box to his office and instructed his secretary to call the police.

O'Donnell said he had warned pupils about the weapon policy but had concentrated mostly on pupils who use lunch boxes, for example, to hit other pupils. "I frankly never expected to encounter a revolver," he said.