Rana Nisar Ahmed, who had been hearing the case since he was appointed judge of Rawalpindi`s anti-terrorist court no.
III in November 2010, was transferred shortly after the last hearing on June 11.
No new judge has been appointed for the court though a hearing was scheduled for today, sources told PTI.
The case was placed before a duty judge, who adjourned it till June 25, they said.
The sources said it was expected that a new judge would be appointed before the next hearing.
Ahmed`s transfer marked the fourth change of the judge conducting the trial of the Pakistani suspects.
Ahmed had also been conducting the trial of five suspects charged with involvement in the 2007 assassination of former premier Benazir Bhutto.
He was transferred hours after he issued a permanent arrest warrant for former President Pervez Musharraf for failing to cooperate with investigators probing Bhutto`s assassination.
Ahmed had constantly pushed prosecutors to ensure Musharraf`s appearance in court.
Experts said Ahmed`s sudden transfer could affect proceedings in the Mumbai attacks case as any new judge will need time to acquaint himself with the details of the complex case.
The trial has been marred by delays and technical hitches since proceedings began in 2009.
At least one of the three judges who previously heard the case was changed after he received threats from militant groups, sources said.
Shahbaz Rajput, one of the lawyers defending the seven suspects, said the repeated changes of the judge was affecting proceedings and delaying the case.
"The accused are suffering for no reason," he told PTI.