A wrist unit of an industrial robot including an eccentric rocking-type reduction gear. The eccentric rocking-type reduction gear includes a hollow forming part forming a hollow part along the rotation center axial line; a through shaft supported rotatably at the hollow forming part and passing through the hollow part to transmit a rotation from the third wrist drive motor from a first wrist element side to a second wrist element side; a plurality of crankshafts arranged around the through shaft and having input gears at ends of the side of the first wrist element; and a gear member provided rotatably centered about the rotation center axial line, the gear member having a first gear to which a rotational force from the second wrist drive motor is input and a second gear with which the input gears of the plurality of crankshafts engage.