Provided is a pulse wave propagation detection system including an electrocardiographic signal detection unit, and an eyeground image detection unit for detecting an eyeground image in synchronization with an electrocardiographic signal detected through the detection unit, which system further includes a correlation unit for correlating a change in the diameter of an eyeground vein--which diameter is measured, at the optic papilla, by use of an eyeground image synchronized with an arbitrary electrocardiographic signal--with the state of pulse wave propagation through an intracerebral blood vessel or with the state of sclerosis of a capillary artery.