The accused, whose name was withheld, was arrested from Haidergad in Barabanki district yesterday, they said.
He was produced before a local court which remanded him in police custody till March 14.
Crime Branch had arrested nine persons, including three advocates, on charges of forgery by using back-dated stamp papers last Friday.
Police had seized 15,500 stamp papers (with face value of Rs seven lakh) from courts at Esplanade, Bandra and Andheri.
Of these, around 300 stamp papers were found to be fake.
Police had arrested Rajbahadur Yadav (45), Sarnath Mangalgi alias Nilesh (30), Mohammad Sheikh (30), Vimlendu Dwevedi (44), Nagendra Tiwari (35) Sudhir Baranwal (23), besides advocates Ravindra Tiwari (30), Haridas Prajapati (30) and Vivek Pande (30).
They were booked under relevant provisions of the IPC for forgery, forgery for purpose of cheating, forgery of valuable security, making or possessing counterfeit seal among others.