His lawyers said it was too dangerous for Mr Musharraf to appear in court yesterday. It was the third time since the high treason proceedings began that explosives have been found along the path the former president is supposed to take to court.
The treason case is the most serious of the legal troubles Mr Musharraf, 70, has faced since he returned to Pakistan in March hoping to contest elections.
Officials scanning the route to court spotted the latest device along a road about a mile from Mr Musharraf's farmhouse on Islamabad's outskirts.
One of his lawyers told the three-member panel of judges hearing the case there were "many security issues" preventing Mr Musharraf's appearance and the court would be responsible if anything went wrong.
Mr Musharraf took power in a 1999 coup and the case relates to the state of emergency he imposed in 2007 and the detention of judges.