http://www.garnstudio.com/lang/us/pattern.php?id=505&lang=us

I am wondering about the gauge. It says 17 stitches times 22 rows 10 by 10cm in stockinette stitch. Does that mean it should be 17 stitches in 10 cm?

Yes, it's 10x10 cm just like it would be 4x4". However you do want to cast on about 24 sts or so to make it a little larger and measure how the sts over just 4" or 10cm, whichever measure you prefer. Your goal is to get 17 sts over that measurement, and the row gauge may not need to match, you just knit to the measurements given for the lengths.