Even as suspicion lingered that he was part of a conspiracy, Mumtaz Qari denied that he was influenced by any political or religious group.
Qadri was produced in the anti-terrorism court in Rawalpindi amidst tight security and the judge recorded his confession under Section 164 of the Code of Criminal Procedure.
The judge subsequently remanded him to judicial custody for a fortnight and sent him to Adiala Jail.
The assassin, who was part of an Elite Force unit assigned to guard Taseer, told the court that he killed the Governor after attending a religious gathering in Rawalpindi.
Qadri said he decided to murder Taseer after speakers at the gathering accused the Governor of committing blasphemy.
Qadri told the judge that he had committed the murder on his own and denied that he was influenced by any political or religious group.
He said he had not discussed matter with anyone and that he had been planning the killing for more than three days when he was deployed to guard Taseer last week.
Even before Qadri`s confession, an official of the Pakistan Electronic Media Regulatory Authority was detained for his alleged role in motivating Qadri.
Police have also sought arrest warrants for Qari Hanif and Syed Ishtiaq Shah, who were running a madrassa in Rawalpindi.
Qari Hanif, a cleric, is believed to have motivated Qadri.
Qadri gunned down Taseer in a posh market in the heart of Islamabad on January 4.
He surrendered immediately after shooting Taseer and said he was angered by the Governor`s criticism of the blasphemy law.
Investigators are yet to determine whether Qadri acted alone or was part of a wider conspiracy.
Senior leaders of the ruling Pakistan People`s Party and security experts have expressed concerns at the lack of action by other members of Taseer`s security detail when Qadri opened fire.
The other bodyguards did not act as human shields or shoot Qadri to incapacitate him.
PPP leaders have suggested that Taseer`s killing had "political motives".
They have criticised the PML-N government in Punjab for perceived lapses in Taseer`s security.
Qadri will be presented in the anti-terrorism court again on January 24.