The 53-year-old professor, who taught law at Leibnitz University in the city of Hanover, is said to have pocketed 153,750 euros ($240,719) in bribes in exchange for accepting students as doctoral candidates although they did not meet the necessary academic requirements.
Of the 68 students accepted by the professor, only 10 went on to obtain the title of doctor.
The professor provided a court in the town of Hildesheim with a full confession on Wednesday. He said he received the money from a consulting firm, which provided him with the candidates.
Not just doctorates-for-cash
During an earlier hearing, a female student of the professor was fined 1,800 euros for trading sexual favors for inflated grades that got her a plum job at the university.
Concerning his motive for corruption, the professor said his net salary of around 5,000 euros ($7,828) was not sufficient for paying back his debts.
A case against the 52-year-old director of the consulting firm is being handled separately, with a verdict expected next week. The consultancy is alleged to have earned large amounts through transactions -- up to 22,000 euros for a single doctorate -- from lawyers aiming to boost their standing by acquiring a doctorate.
The problem of falsely awarded doctorates is said to be widespread in Germany, where academic degrees are particularly highly regarded.