Singhal was presently posted as Director General of Vigilance Bureau, an official spokesman said here.
He has replaced S N Vashisht, who has been posted as Director General of State Vigilance Bureau in place of Singhal.
No reason for the changes at the highest level in the Haryana Police and State Vigilance Bureau was given.
Vashisht was appointed to the post during the Bhupinder Singh Hooda-led Congress government.