Provided is a motor rotor having a magnet attachment structure that can be used in a severe environment, for example. A motor rotor comprises: a rotary shaft; an annular magnetic body; a metal member; and an annular magnet that surrounds the magnetic body. The magnetic body has two surfaces that face each other in the rotary shaft direction, and a protruding part that protrudes from one surface of the two surfaces in the rotary shaft direction. The protruding part surrounds the rotary shaft. The magnet has two surfaces that face each other in the rotary shaft direction. The metal member is disposed on one surface of the magnet. The metal member surrounds the protruding part. The metal member is interposed between the protruding part and the one surface of the magnetic body.