The shark attack was reported at 10:58 a.m. Tuesday near Vandenberg Air Force Base.
The Santa Barbara County Sheriff's Department received the 911 call that a man had been bitten by a shark while surfing near Surf Beach in Lompoc.
A friend who was surfing with the victim witnessed the attack. He assisted the victim and pulled him to shore. He administered first aid while a third surfer called 911.
Vandenberg Air Force Base Fire Dept. personnel took over emergency procedures. The victim was pronounced dead at the scene by paramedics.
The victim was identified as 39-year-old Orcutt resident Francisco Solorio Jr. He was bitten in the upper torso area, according to the sheriff's department.
It was not immediately clear what type of shark attacked the victim. The details of the attack were under investigation. The beach was closed during the investigation.