A vehicle steering system, comprising: a steered shaft that transmits a force for steering a steered wheel, to the steered wheel via a tie rod; a housing that is connected to a vehicle body, and that supports the steered shaft such that the steered shaft is able to reciprocate its motion in an axial direction of the steered shaft; an acceleration sensor that is attached to the housing or the tie rod; an inverse input vibration estimation unit that estimates an inverse input vibration input into the tie rod from the steered wheel side, based on a signal output from the acceleration sensor; and an inverse input vibration transmission unit that transmits the inverse input vibration estimated by the inverse input vibration estimation unit to a steering member that is operated to steer a vehicle, wherein the inverse input vibration estimation unit includes: a Fast Fourier transform processing unit that converts the signal output from the acceleration sensor, which is a time-domain signal, into a frequency-domain signal; an extraction unit that extracts a frequency-domain signal, of which a frequency falls within a predetermined range and of which a power density falls within a predetermined range, from the frequency-domain signal obtained by the Fast Fourier transform processing unit; and an Inverse Fast Fourier Transform processing unit that extracts an inverse input vibration component contained in the signal output from the acceleration sensor by converting the frequency-domain signal extracted by the extraction unit into a time-domain signal. a steered shaft that transmits a force for steering a steered wheel, to the steered wheel via a tie rod; a housing that is connected to a vehicle body, and that supports the steered shaft such that the steered shaft is able to reciprocate its motion in an axial direction of the steered shaft; an acceleration sensor that is attached to the housing or the tie rod; an inverse input vibration estimation unit that estimates an inverse input vibration input into the tie rod from the steered wheel side, based on a signal output from the acceleration sensor; and an inverse input vibration transmission unit that transmits the inverse input vibration estimated by the inverse input vibration estimation unit to a steering member that is operated to steer a vehicle, wherein the inverse input vibration estimation unit includes: a Fast Fourier transform processing unit that converts the signal output from the acceleration sensor, which is a time-domain signal, into a frequency-domain signal; an extraction unit that extracts a frequency-domain signal, of which a frequency falls within a predetermined range and of which a power density falls within a predetermined range, from the frequency-domain signal obtained by the Fast Fourier transform processing unit; and an Inverse Fast Fourier Transform processing unit that extracts an inverse input vibration component contained in the signal output from the acceleration sensor by converting the frequency-domain signal extracted by the extraction unit into a time-domain signal. a Fast Fourier transform processing unit that converts the signal output from the acceleration sensor, which is a time-domain signal, into a frequency-domain signal; an extraction unit that extracts a frequency-domain signal, of which a frequency falls within a predetermined range and of which a power density falls within a predetermined range, from the frequency-domain signal obtained by the Fast Fourier transform processing unit; and an Inverse Fast Fourier Transform processing unit that extracts an inverse input vibration component contained in the signal output from the acceleration sensor by converting the frequency-domain signal extracted by the extraction unit into a time-domain signal.