A turbomachinery includes a labyrinth seal (2) to prevent unstable vibration of a rotor formed by dividing the seal into segments (7) in a circumferential direction and combining the segments (7) whose comb teeth (5) differ in height. The labyrinth seal (2) preferably includes two kinds of segments (7) whose comb teeth (5) differ in height for each kind of segment, and the segments (7a) of the greater comb tooth height are arranged in a certain reference direction on a cross section right-angled to a rotational axis, and in a direction opposite to the reference direction, and the segments (7b) of the smaller comb tooth height are arranged in a direction right-angled to the reference direction, and in a direction opposite to that right-angled to the reference direction.