Ventilated type brake disc rotor

A ventilated type brake disc rotor comprising:

• an inboard sliding plate and an outboard sliding plate that are shaped annular and are disposed opposite to each other in an axle direction;
• and
• joints that are formed to connect between the inboard sliding plate and the outboard sliding plate, and are arranged along lines extending in a circumferential direction of the inboard sliding plate and the outboard sliding plate,
• wherein:
• the joints include first joints arranged along a first line and second joints arranged along a second line located in an outer side with respect to the first line in a radial direction of the inboard sliding plate and the outboard sliding plate;
• each of the second joints includes a first width part and a second width part formed in an inner side with respect to the first width part in the radial direction;
• the first width part is constant in circumferential width, and has a substantially rectangular cross section;
• and
• the second width part is less in circumferential width than the first width part, and is shaped to decrease in circumferential width as going inwardly in the radial direction.