Abstract: This lift axle device comprises: a first air spring which corresponds to a first axle; a second air spring which corresponds to a second axle that reciprocates between a down position and lift position; an air bellows; a pneumatic circuit which has a solenoid valve; and a control circuit. The control circuit controls the supply of electric power to the solenoid valve. If the pressure transitions to less than a first pressure, the second axle is placed in the lift position. If the pressure transitions to at least a second pressure, the second axle is placed in the down position. If the pressure transitions to at least the first pressure and less than the second pressure, the second axle is caused to maintain the position thereof.