A torque estimation method according to the present disclosure estimates a value of shaft torque of a rotary motion transmitting mechanism. The torque estimation method includes: a step of specifying a maximum value of a torsion angle between an input shaft and an output shaft from the time when a measurement value of the torsion angle is zero to the time when the value of the shaft torque is estimated; and a step of specifying the maximum value of the torsion angle. In the step of specifying the maximum value of the torsion angle, the maximum value of the torsion angle is specified based on a difference between the measurement value of the torsion angle subjected to low-pass filter processing at a first cutoff frequency and the measurement value of the torsion angle subjected to low-pass filter processing at a second cutoff frequency.