Arterial stiffness is used to diagnose atherosclerosis. The most commonly used estimation methods are indirect and non-invasive. To develop a method for direct measurement of the stiffness of blood vessels, stiffness estimation was performed on four simulated blood vessels with different stiffnesses values using a balloon catheter employed in the treatment of atherosclerosis. To measure the pressure response during balloon dilation in a simulated blood vessel, a pressurization and pressure measurement device was fabricated to pressurize the balloon catheter at a constant speed while measuring the pressure. To calculate Young’s moduli of the simulated vessels, we simultaneously measured the pressure responses of the simulated blood vessels and the changes in circumferential length of the vessels using a microscope. A tensile test was also used to measure the Young’s moduli of the simulated vessels. The Young’s modulus values obtained by the balloon catheter method and the tensile test were compared. A linear relationship was observed between the Young’s moduli determined by the two tests, indicating that the balloon catheter method can be used to estimate the Young’s modulus of simulated blood vessels. To develop a simple method for estimating vessel stiffness, we calculated the reaction force received from a simulated vessel using the pressure difference during dilation in three balloon catheters with different diameters. We then evaluated whether the stiffness could be estimated by comparing the measured pressures with the Young’s modulus values. Both the peak pressure after pressurization and the steady-state pressure during pressurization were related to the Young’s modulus values, although the relationship depended on the diameter of the balloon catheter. Therefore, we suggest that it is possible to obtain values that reflect the Young’s moduli of blood vessels using the balloon catheter method. These results suggest that with appropriate optimization of the balloon catheter diameter relative to the vessel diameter, this approach has the potential to provide pressure response values reflecting the stiffness of blood vessels.