Bean counter is a slang term. The term is used to refer to a person who makes decisions using mathematical calculations. For example, an accountant or a financial officer. The term was first used during the 1970s, as a description of financial comptrollers and accountants who showed an abnormal amount of interest in even the minutest details of a company's finances.
Originally, almost anyone employed in accounting fields was informally described as a bean counter, with little to no pejorative meaning attached. However, now, the term bean counter is often used negatively to describe an overly zealous or fastidious accountant.
The title of bean counter has not exactly been a positive one for accountants. Many people hold bean counters responsible for the dismantling or cancellation of programs due to budgetary concerns.