A multi-stage dry pump comprising: a plurality of pump chambers (11, 12, 13, 14, 15) each including a cylinder (31, 32, 33, 34, 35) and a rotor (21, 22, 23, 24, 25) housed in the cylinder (31, 32, 33, 34, 35); a first rotor shaft (20, 20a) that is a rotation shaft of the rotors (21, 22, 23, 24, 25); a fixed bearing that rotatably supports the first rotor shaft (20, 20a) and restricts a movement thereof along an axis direction of the first rotor shaft (20, 20a); and a free bearing that rotatably supports the first rotor shaft (20, 20a) and permits a movement thereof along the axis direction of the first rotor shaft (20, 20a); wherein: the plurality of pump chambers (11, 12, 13, 14, 15) is disposed between the fixed bearing and the free bearing; and the plurality of pump chambers (11, 12, 13, 14, 15) is disposed from the fixed bearing to the free bearing such that an aspiration-side pressure of the pump chambers (11, 12, 13, 14, 15) increases in sequence from the fixed bearing to the free bearing, characterized by an electrical motor that is disposed on an opposite side of the fixed bearing with respect to the free bearing and that applies a rotational drive force to the first rotor shaft (20, 20a); a second rotor shaft that is a rotation shaft for another plurality of the rotors; and a timing gear that is disposed between the fixed bearing and the electrical motor, and that transmits a rotational drive force from the first rotor shaft (20, 20a) to the second rotor shaft. a plurality of pump chambers (11, 12, 13, 14, 15) each including a cylinder (31, 32, 33, 34, 35) and a rotor (21, 22, 23, 24, 25) housed in the cylinder (31, 32, 33, 34, 35); a first rotor shaft (20, 20a) that is a rotation shaft of the rotors (21, 22, 23, 24, 25); a fixed bearing that rotatably supports the first rotor shaft (20, 20a) and restricts a movement thereof along an axis direction of the first rotor shaft (20, 20a); and a free bearing that rotatably supports the first rotor shaft (20, 20a) and permits a movement thereof along the axis direction of the first rotor shaft (20, 20a); wherein: the plurality of pump chambers (11, 12, 13, 14, 15) is disposed between the fixed bearing and the free bearing; and the plurality of pump chambers (11, 12, 13, 14, 15) is disposed from the fixed bearing to the free bearing such that an aspiration-side pressure of the pump chambers (11, 12, 13, 14, 15) increases in sequence from the fixed bearing to the free bearing, characterized by an electrical motor that is disposed on an opposite side of the fixed bearing with respect to the free bearing and that applies a rotational drive force to the first rotor shaft (20, 20a); a second rotor shaft that is a rotation shaft for another plurality of the rotors; and a timing gear that is disposed between the fixed bearing and the electrical motor, and that transmits a rotational drive force from the first rotor shaft (20, 20a) to the second rotor shaft. the plurality of pump chambers (11, 12, 13, 14, 15) is disposed between the fixed bearing and the free bearing; and the plurality of pump chambers (11, 12, 13, 14, 15) is disposed from the fixed bearing to the free bearing such that an aspiration-side pressure of the pump chambers (11, 12, 13, 14, 15) increases in sequence from the fixed bearing to the free bearing, characterized by an electrical motor that is disposed on an opposite side of the fixed bearing with respect to the free bearing and that applies a rotational drive force to the first rotor shaft (20, 20a); a second rotor shaft that is a rotation shaft for another plurality of the rotors; and a timing gear that is disposed between the fixed bearing and the electrical motor, and that transmits a rotational drive force from the first rotor shaft (20, 20a) to the second rotor shaft.