Leicestershire County Council has confirmed that Snibston Discovery Museum will close due to cuts.
Councillors voted by a majority of 28 to 24 not to pass a motion to give more time to work with the Friends of Snibston to try to produce a viable plan for the attraction.
The news will come as a blow to campaigners who were protesting outside County Hall.
Over the next four years the county council needs to make more than £80 million of savings.
Leader of Leicestershire County Council, Nick Rushton said, “We cannot afford to keep running Snibston Discovery Museum in its current form, at a time when we have to save £120 million by 2019.
“Over the last year, we’ve given the Friends of Snibston ample time and information to progress their alternative proposals but, despite three attempts, their proposals remain financially unviable. This judgement is supported by an independent assessor.”
According to the county council, the total cost of running Snibston last year was £790,000. If the council did not make any changes, this cost would rise to £900,000 per year.