A measurement device can detect a degree of bending of a linear body with a sensor when compressive force in a direction of longitudinal axis is applied to the linear body as a result of contact of a tip end of the linear body with an obstacle. Then, the detected degree of bending of the linear body is converted to compressive force in the direction of longitudinal axis applied to the linear body based on predetermined correlation between the degree of bending and the compressive force, so that presence of an obstacle in a direction of travel of the linear body can be sensed based on increase in the compressive force. In addition, as the same measurement device is applicable to linear bodies of various shapes and materials, cost effectiveness is achieved.