A contact force measurement method for measuring, in a vibration damping structure in which a tube bundle disposed in a fluid is supported by a vibration damping member inserted between tubes included in the tube bundle, a contact force applied to the tube bundle from the vibration damping member by a probe inserted into each tube, the method comprising: a characteristic data preparation step of previously preparing characteristic data defining a relationship between a value measured by the probe and the contact force; a measurement value acquisition step of inserting the probe into the tube and acquiring a measurement value measured by the probe; and a contact force calculation step of calculating the contact force corresponding to the measurement value, based on the characteristic data, characterized in that the measurement value acquisition step includes acquiring positional information of the probe in conjunction with the measurement value while scanning the probe within the tube, and associating and storing the measurement value and the positional information, wherein the characteristic data preparation step includes: performing a load test while applying a predetermined load simulating the contact force to a sample corresponding to the tube supported by the vibration damping member and acquiring a measurement value measured by the probe inserted into the sample to generate the characteristic data, generating first characteristic data based on the measurement value acquired by applying the predetermined load on opposite sides so as to sandwich the tube from both sides at a substantially same position along an axial direction of the sample, and generating second characteristic data based on the measurement value acquired by applying the predetermined load on opposite sides so as to sandwich the tube at different positions along the axial direction of the sample, and wherein the contact force calculation step includes using the first characteristic data or the second characteristic data as the characteristic data, based on a positional relationship between the tube and the vibration damping member. a characteristic data preparation step of previously preparing characteristic data defining a relationship between a value measured by the probe and the contact force; a measurement value acquisition step of inserting the probe into the tube and acquiring a measurement value measured by the probe; and a contact force calculation step of calculating the contact force corresponding to the measurement value, based on the characteristic data, characterized in that the measurement value acquisition step includes acquiring positional information of the probe in conjunction with the measurement value while scanning the probe within the tube, and associating and storing the measurement value and the positional information, wherein the characteristic data preparation step includes: performing a load test while applying a predetermined load simulating the contact force to a sample corresponding to the tube supported by the vibration damping member and acquiring a measurement value measured by the probe inserted into the sample to generate the characteristic data, generating first characteristic data based on the measurement value acquired by applying the predetermined load on opposite sides so as to sandwich the tube from both sides at a substantially same position along an axial direction of the sample, and generating second characteristic data based on the measurement value acquired by applying the predetermined load on opposite sides so as to sandwich the tube at different positions along the axial direction of the sample, and performing a load test while applying a predetermined load simulating the contact force to a sample corresponding to the tube supported by the vibration damping member and acquiring a measurement value measured by the probe inserted into the sample to generate the characteristic data, generating first characteristic data based on the measurement value acquired by applying the predetermined load on opposite sides so as to sandwich the tube from both sides at a substantially same position along an axial direction of the sample, and generating second characteristic data based on the measurement value acquired by applying the predetermined load on opposite sides so as to sandwich the tube at different positions along the axial direction of the sample, and wherein the contact force calculation step includes using the first characteristic data or the second characteristic data as the characteristic data, based on a positional relationship between the tube and the vibration damping member.