A rotor of the invention includes a core made of laminated steel sheets and formed with a rotation-transmitting-member mounting end face (a wall surface of a through hole for shaft) extending over a lamination direction and a rotation transmitting member (a shaft) mounted to the rotation-transmitting-member mounting end face of the core. The core is formed with a welding end face (a wall surface of a through hole for welding) extending over the lamination direction and in a position adjacent to a rotation-transmitting-member mounting end face. A welded trace is formed in the welding end face, extending to the rotation transmitting member and over the lamination direction of the core. The invention can easily achieve size reduction and weight reduction of a rotary machine and manufacture a rotor in the reduced number of working processes.