Provided is an optical characteristic measuring probe which can detect the position and the direction of the leading end of the probe without affecting a monitoring image. The bendable optical characteristic measuring probe is provided with a light guide body (71), which transmits light emitted from a light source and irradiates a subject to be measured with light, and a guide tube (70), which holds the light guide body (71) such that the light guide body freely rotates about the axis and is freely displaced in the axis direction. The light guide body (71) guides at least two types of light, i.e., measuring light for measuring the optical characteristics of the subject to be measured, and position determining light for measuring the position of the light guide body. On the side surface of the guide tube (70), a mark (M) having the characteristics of transmitting the measuring light and returning only the position determining light to the light guide body is provided.