The incident was reported from Uttam Nagar (West) Metro Station around 11:15 am, police said.
The victim, Hans Ram Barla, was posted in the security wing of Delhi Police and was on medical leave for the last one month.
He was undergoing treatment for abdominal tuberculosis, police said.
A suicide note was found from the possession of the deceased. In the note, he mentioned that he was committing suicide because of his illness.
Mr Barla is survived by two sons and a daughter.
The Metro services were disrupted on the Blue Line for close to half-an-hour following the incident.