Patent ID: 7713197

Claim:
A pressure measuring device, comprising: contact means for making contact with an object to be measured, in which the object to be measured has a predetermined shape and a pressure is applied in an outward direction from the object to be measured; vibration means which is connected with the contact means and configured to vibrate at a plurality of frequencies upon application of a voltage signal; voltage applying means for applying the voltage signal to the vibration means; measuring means for measuring a current flowing through the vibration means at the plurality of frequencies; and information processing means for determining two resonance points of a system including the object to be measured and for determining the pressure based on the current measured by the measuring means at the plurality of frequencies, wherein the information processing means determines that a first pressure is higher than a second pressure by determining that the first pressure has a lower measured current than the second pressure at frequencies outside a frequency range between the two resonance points and by determining that the first pressure has a higher measured current than the second pressure at frequencies within the frequency range between the resonance points.