Sharper Image Corp., a retailer of unusual gadgets and electronic toys, said sales through its website rose sixfold from Dec. 1 to Dec. 21.

The company, which had revenue of $216.8 million last year, also said same-store sales, or sales at stores open at least a year, rose 9 percent, while mail-order sales rose 27 percent.

Sharper Image is benefiting from sales of its new line of proprietary products – items that the company has begun making for itself. In addition to increasing sales, the items helped boost the company’s gross margin by 2 percentage points from a year ago.

The increase in the important month of December will significantly affect earnings for the year, Sharper Image said.

“As consumers get even more comfortable with online shopping, I expect Internet sales at our sharperimage.com website will continue to increase,”Chairman and Chief Executive Richard Thalheimer said in a statement.

Total sales on the Internet are expected to increase threefold to $3.5 billion in the fourth quarter this year, compared with the same period last year, analysts said. In next year’s fourth quarter, online sales are expected to be in the neighborhood of $8 billion, said Forrester Research senior analyst James McQuivey.

Analysts said Sharper Image is poised to flourish online because of its particularly gizmo-happy clients are more likely to shop on the Internet than the average U.S. consumer.

“They appeal to a slightly higher-educated customer, people that are into technology and gadgets,” said McQuivey. “They’re just the kind of people who would buy on the Web.”

San Francisco-based Sharper Image operates 86 stores throughout the U.S. and mails millions of catalogs each month. Sharper Image rose 2 3/8 to 15 1/4 in late trading.