The woman has admitted to the offence and has been charged with animal cruelty offences.
Police received an anonymous tip in February 2008 and when they investigated the case they found a pony peering through the cellar window of a house in Halland, on the west coast of Sweden.
The cellar was 18 square metres in size and only 178 centimetres high.
When police examined the cellar their found exposed electrical wiring and the remains of a home distilling kit.
Varberg district court heard on Friday that the cellar floor was bare but for manure, and the pony had only dirty water to drink, no food.
The woman told the court that she had planned to sell the horse, which she had owned for only 14 days.
According to a report in the newspaper Aftonbladet the woman was also found to be keeping four cats that were unable to get out as the cat flap was nailed shut, and three hamsters without food in a dirty cage.
The 32-year-old woman has now been served with a ban from keeping animals.