To provide flexibility to a high frequency probe for measurement and to ensure safe and exact measurement in impedance-matched state.

A signal conductor 2 made of a metal plate having flexibility and gradually widening from narrow one end toward the other wide end, and a grounded conductor 3 made of a metal plate having flexibility and gradually widening from narrow one end toward the other wide end are provided. One end of the grounded conductor 3 is made to correspond to the one end of the signal conductor 1 and the other end of the grounded conductor 3 is made to correspond to the other end of the signal conductor 1 to face the signal conductor 2 and the grounded conductor 3. Projected probes are provided at each one end. The ratio of the width of the signal conductor 2 at any position in the longitudinal direction to the intervals of the signal conductor 2 and the grounded conductor 3 is made constant.