An accessory device for a roller skate is disclosed, for use to block the wheels of this roller skate. This device comprises a plurality of elongated members that are made of non-slippery material and sized to snugly fit transversely between two of the wheels. These members are linked together, preferably by an elastic rope which is forming a closed loop. The device can be secured to the frame of the roller skate whenever required by placing each member between two of the wheels to prevent the same from rotating. This device is very advantageous because it is inexpensive and very simple to install on a roller skate. It is also very light in weight and compact, thereby making it easy to carry.