This is called a Tsuma-Taro Vegetable Spiral Cutter. And its a multipurpose machine.
With the flat blade attachment, it can mimic the knife-cutting technique called katsuramuki, cutting around the circumference of a vegetable to create one continuous paper-thin sheet. And if you really wanted to, you could use this blade to make Sashima (thin slices of meat).
It also has a julienne blade attachment so you can cut vegetables in long fine strips.
The spiral cutter is a pretty nifty machine for preparing some fancy vegetable dishes, sushi, or appetizers.