An optical reading device which is capable of being assembled readily and assures stabilization of the distance between a sensor of the reflecting type and a surface of a medium to be read by the sensor. The sensor is carried on a holding member, and an engaging member is pivotally supported on the holding member at a location spaced from the sensor. A screw shaft and a guide shaft extend in parallel to each other and to an axis of pivotal motion of the engaging member. The screw shaft has a spiral groove formed thereon for meshing engagement with a toothed portion formed on the engaging member or the holding member and is rotated to move the holding and engaging members therealong. A record medium to be read by the sensor is fed in a direction perpendicular to the screw shaft. A contact element is provided on the holding member for assuring a minimum distance between the sensor and a surface of the record medium to be read by the sensor. A resilient member is disposed between the holding and engaging members for urging them such that the contact element may be resiliently contacted with a sliding face and the toothed portion may be resiliently engaged with the spiral groove of the screw shaft.