Disclosed are a laundry treatment apparatus and a magnetic gear device. The laundry treatment apparatus includes a cabinet for defining an external appearance of the laundry treatment apparatus, a drum rotatably disposed inside the cabinet for accommodating laundry therein, and a power unit for rotating the drum. The power unit includes a rotational magnetic field generator fixed inside the cabinet for generating a rotational magnetic field, a magnetic flux converter provided radially outside of the rotational magnetic field generator for forming a magnetic path, and a magnetic rotator provided radially outside of the magnetic flux converter, the magnetic rotator having at least one permanent magnet inside thereof.