削り節 vs かつお節

is there any difference between these two ingredient?

They are the same. Basically 削り節 is shreds of かつお節.
In the past people buy a piece of かつお節, and shave then into think slices using a plane like device. But these days shredded かつお節 ＝削り節 is far more popular, because it is handy. They are sold in plastic bags.

鰹節の削り方：出汁（だし）に関わる乾物・山陰ならではの乾物を取り扱っています
How to 'shave' かつお節 into 削り節.

かつお節 and 削り器
http://www.e-dashi.com/images/kezuriki/kezurikata/05.4.25kezurikata4.JPG
削り節 in various thinness and size
http://www.e-dashi.com/images/kezuriki/kezurikata/05.4.25kezurikata5.JPG

In other words, かつお節 can refer both to thin shaved pieces and b-type one which is not so common in these days, whereas 削り節 is not used for the latter.

かつお節 or 削り節


かつお節 (not 削り節)