A fluid machine includes: a shaft portion extending in an axis direction; a shroud provided to surround the shaft portion, and forming a flow path between the shroud and the shaft portion, the flow path having one side in the axis direction serving as an upstream side and another side in the axis direction serving as a downstream side; a first propeller provided rotatably around the axis between the shaft portion and the shroud; a second propeller provided rotatably around the axis between the shaft portion and the shroud on the downstream side of the first propeller; an outer periphery driving motor provided in the shroud and configured to rotationally drive the first propeller; and an inner periphery driving motor provided in the shaft portion and configured to rotationally drive the second propeller in a direction opposite to the rotational direction of the first propeller.