A wear amount estimation method for estimating a wear amount of aircraft tires in a state of taxiing indicating a state in which an aircraft runs on a ground under a power of the aircraft, the state of taxiing including a state of a free rolling run indicating a state in which the aircraft runs straight by rolling without braking force acting on the aircraft tires, the method comprising: calculating wear energy E P, which depends on an internal pressure of the aircraft tires, based on wear energy E FR of the aircraft tires in the state of the free rolling run, which is changed on the basis of the internal pressure, and positions of ribs of the aircraft tires; calculating wear energy E L, which depends on a load acting on the aircraft tires, based on the wear energy E FR, which is changed on the basis of the load, and the positions of the ribs; calculating wear energy E V, which depends on a velocity of the aircraft, based on the wear energy E FR, which is changed on the basis of the velocity, and the positions of the ribs; calculating wear energy ΔE S, which depends on a slip angle caused in the aircraft tires, based on the wear energy E FR, which is changed on the basis of the slip angle, and the positions of the ribs; calculating wear energy ΔE B, which depends on a braking force of the aircraft, based on the wear energy E FR, which is changed on the basis of the braking force, and the positions of the ribs; and estimating the wear amount of the aircraft tires based on the wear energy E P, the wear energy E L, the wear energy E V, the wear energy ΔE S, the wear energy ΔE B, and a wear resistance R indicating a relationship between predetermined wear energy and a predetermined wear amount, wherein the wear energy E FR is acquired previously, and the ribs are defined by a plurality of circumferential grooves extending in a tire circumferential direction on the tread tracks of the aircraft tires. calculating wear energy E P, which depends on an internal pressure of the aircraft tires, based on wear energy E FR of the aircraft tires in the state of the free rolling run, which is changed on the basis of the internal pressure, and positions of ribs of the aircraft tires; calculating wear energy E L, which depends on a load acting on the aircraft tires, based on the wear energy E FR, which is changed on the basis of the load, and the positions of the ribs; calculating wear energy E V, which depends on a velocity of the aircraft, based on the wear energy E FR, which is changed on the basis of the velocity, and the positions of the ribs; calculating wear energy ΔE S, which depends on a slip angle caused in the aircraft tires, based on the wear energy E FR, which is changed on the basis of the slip angle, and the positions of the ribs; calculating wear energy ΔE B, which depends on a braking force of the aircraft, based on the wear energy E FR, which is changed on the basis of the braking force, and the positions of the ribs; and estimating the wear amount of the aircraft tires based on the wear energy E P, the wear energy E L, the wear energy E V, the wear energy ΔE S, the wear energy ΔE B, and a wear resistance R indicating a relationship between predetermined wear energy and a predetermined wear amount, wherein the wear energy E FR is acquired previously, and the ribs are defined by a plurality of circumferential grooves extending in a tire circumferential direction on the tread tracks of the aircraft tires.