The court also extended his custody till the next date of hearing which has been fixed for May 14.
Aseemanand had moved the bail application on the grounds that he had been kept in custody for more then 90 days and that probe agencies had failed to file a charge sheet against him. He cited Section 167 (2) of the CrPC which states that a person cannot be kept in custody for more than 90 days without filing of a charge sheet.
Opposing the same, the NIA had contented that since the matter concerns national security, the investigation cannot be done hastily and as such the bail plea should be rejected.
The court, without expressing any opinion on the merits of the case, dismissed his bail application.
Apart from Ajmer Dargah blast, which claimed three lives and left 15 others injured, Aseemanand is an accused in several other blast cases across the county including those at Hyderabad`s Mecca Masjid, Samjhauta Express and Malegaon.
He was arrested in January this year in the dargah blast case.
The CBI court here was recently given charge of the trial of cases to be prosecuted by the NIA, pursuant to which Asseemaanand and another accused Bharat Bhai were produced in court.
The NIA was handed over the investigation in the case on April 6. Earlier, ATS-Rajasthan was probing the bomb attack at the dargah of Sufi saint Khawaja Moinuddin Chishti.
The ATS-Raj has already chargsheeted Devendra Gupta, Lokesh Sharma and Chandrasheker in a Ajmer court. However, Chandrasheker has been successful in obtaining bail from High Court.
The NIA has also chargesheeted two accused - Harshad Solanki and Mukesh Vasani- in the blast case before the CBI court here last month.