To provide an easily-handling inexpensive optical element in a minute size having no electric or magnetic influence or no noise by connection or the like and having both functions of light emission and light reception without influenced by the noise or the loss accompanied by transmission of light signals, and to provide a compact optic sensor having high sensitivity for obtaining accurately measured values by using the above optical element.

The element is obtained by integrating a waveguide formed by irradiating a film made of a photosensitive polymer material or the like with light or a branched optical fiber, a light emitting element and a light receiving element disposed on both ends of the waveguide or fiber, and light emitting and light receiving circuits and an indication circuit on a supporting substrate.