We report direct optical reading of resistive switching in an amorphous TiO2 film. Changing TiO2 film conductivity under an applied electric field causes a change in the film reflection coefficient. To find this phenomenon, a sample with Al electrodes deposited on an amorphous TiO2 film in the form of an interdigital transducer was used. The experimental characteristic of a device shows a hysteresis of the reflection coefficient repeating the change in resistance under an applied electric field.