A rotary machine is provided with: a bearing that supports a rotary shaft of an impeller; a bearing support part that supports an outer circumference of the bearing; a key groove that is formed in the bearing and the bearing support part and extends along a rotary shaft line direction of the rotary shaft; and a key member that is inserted into the key groove. The bearing support part is provided with an outer regulating part that can contact one end part of the key member inside the key groove. An outer ring of the bearing is provided with an inner regulating part that can contact another end part of the key member inside the key groove. A distance between the outer regulating part and the inner regulating part is longer than a length of the key member in the rotary shaft line direction.