Photoelastic sensing means, and more particularly photoelastic sensing means capable of providing high sensitivity for measuring pressure, force, displacement, acceleration or inertial force, proximity, temperature and other measurands. The photoelastic sensing means comprises a thin photoelastic member of transparent material having closely spaced top and bottom outer surfaces with peripheral edges and an edge surface extending between the peripheral edges of the other surfaces. Light flux is provided to the edge surface of the member at a first region for transmission by the member along a path to a second region at the edge surface where it is received and detected. The spacing between the top and bottom outer surfaces of the member is relatively small compared to the length of the path of the light flux in the member. The member is supported to produce bending stresses in the member in a direction transverse to the path of the light flux in the member with the application of force to the member. An output signal is provided responsive to the force which produces the stress in the member.