A composite material bicycle disc brake rotor is provided for a bicycle disc brake device and is designed to be mounted to a bicycle wheel hub directly or using a hub mounting member. The rotor basically includes a rotor member and a fastening member. The rotor member has a first ring-shaped member and a pair of second ring-shaped members disposed on opposite sides of the first member. The second members include a material with higher wear resistance than the first member. At least one fixing hole is formed through the first and second members and a depression is formed around the fixing hole on the surface of one of the second members. The fastening or tightening member is mounted through the fixing hole of the rotor member to fix the rotor member to another member.