A linear-rotary actuator includes a rotor and a stator. The rotor includes an output shaft, and makes a linear motion in an axial direction and a rotary motion in a circumferential direction. The rotor includes N and S pole portions alternating with each other in the axial direction as seen in the circumferential direction and alternating with each other in the circumferential direction as seen in the axial direction. The stator includes a linear motion winding, a rotary motion winding, and protruding cores. The protruding cores protrude toward an inner circumferential side of a radial direction to be opposed to the rotor. The protruding cores are arranged in the axial direction and in the circumferential direction, and displaced in the axial direction to form a circumferential line skewed relative to a direction in which the rotor makes the rotary motion.