Arafat Ali was attempting to throw a bomb on Friday at police who had surrounded his hideout in Rafah, on the border with Gaza, when it exploded, security sources said.
Sources said he was second-in-command of a group called Tawhid wal Jihad, which the authorities say had carried out a series of attacks in Sinai since October 2004.
Nineteen people, mainly Egyptians, died in the group's last attack in Dahab, while scores more were killed in bombings at resorts in Taba and Sharm el-Sheikh.
The interior ministry announced earlier this month that Nasser Khamis al-Mallahi, the head of the organisation, was killed in a gun battle with police.
Earlier this month three suspects in the Dahab bombing attacks were killed, along with an Egyptian police officer, during a clash in the northern Sinai.