Tesla CEO Elon Musk. Reuters Ron Baron, CEO of Baron Capital Group, believes that Tesla is going to grow and grow and grow.

He said that the electric-car maker could grow to be "one of the largest companies" in the world during an interview with CNBC on Tuesday.

"I think there is a very good chance I could own this stock for 10, 15, 20 years," said Baron, who predicted that he would make $6 billion or $7 billion over that time frame.

"I think this could be one of the largest companies in the United States, in the whole world, one of the largest," he said.

When asked by CNBC if he was concerned that Tesla CEO Elon Musk had over-promised car completions, possibly to pump up the firm's secondary stock offering, Baron rebuffed the idea.

Musk "actually took less money on the last offering than he was offered," said Baron. "So no, I don't think he'll be back to the market for quite a while, if he's ever going to be back to the market for equity again."

Tesla announced that it would offer 6.8 million new shares, worth approximately $1.46 billion, on May 18. This came two weeks after the company reported earnings and announced that it would move up it's target of 500,000 cars completed annually by two years, to 2018 from 2020. The stock offerings price, however, was priced below the company's previous offering.

Baron believes that the company cannot only complete that order goal, but also produce more electric batteries in that time.

Baron, whose funds have roughly $20 billion in assets and is known to invest over the long term, has built up an investment of around $300 million over the past year and a half. According to Baron, he has not made much in terms of profit on the trade since they bought the shares for $208 to $210 a share on average.

He recognized that there have been worries over Tesla's future, but he has faith in its development and keeps close tabs on the firm.

"Every three or four months I go and visit the factory and I make sure it's developing the way that I expect it to develop," Baron said. "And if it doesn't develop the way I expect it to develop, then I would sell my stock. I'm not engaged to be married, not going to marry it, I don't care."

To check out the whole interview, head over to CNBC »