Grace Teal set up Trinity Self Drive, a van and car-hire company on North Street, Gainsborough, in August last year, and she also runs Luxe Prestige, which is a vehicle leasing service.
The fire at the Trinity Self Drive offices happened on Thursday, October 7.
Grace said: “As the business owner I feel absolutely gutted that somebody would target our premises in an unprovoked attack .
"This is also worrying as it could have spread if it hadn’t been spotted in time. It could have caused the houses behind us to catch fire s.
“Myself and my colleague arrived on scene to find that unknown persons had broken into the office, gaining access by ripping off a back panel and pushing their way through.
"They carried out a search inside the building, sprayed graffiti on the floor using our own floor marker and then set an intentional fire.
"The fire brigade stated they believe it had been set in the early hours of the morning and was smouldering for some time before it picked up momentum at around 6am, when it was seen.
“Being a woman in business, in an industry recognised as predominantly male, it has taken a lot of confidence and hard work to get where we are and somebody has tried to snatch that away before my eyes.”
A spokesman from Lincolnshire Police said: “We were called to reports of a fire at a property on North Street, Gainsborough at 7.20am on October 7.
"It was believed to have happened in the early hours and it's also believed that the fire was deliberately ignited. Lincolnshire Fire and Rescue were also in attendance.
“This is being investigated and we would urge members of the public to come forward if they have any information that can assist with our enquiries.
"Contact us on 101 quoting incident 54 of October 7.”
Grace added: “As a new resident to Gainsborough we were warned of ongoing crime but we did not let this put us off because we knew we had a purpose and we could really help out the town.
“I myself see the town as a beautiful place with so much potential.”