An optical distance measuring sensor includes a light receiving element arranged on the same plane as a light emitting element. The light receiving element includes a light receiving unit having a plurality of cells and collecting the light emitted from the light emitting element and reflected by a target object, a flash memory unit storing a predetermined position on the light receiving unit, and a signal processing circuit unit sensing the collection position of the light on the light receiving unit, and measuring the distance to the target object based on a relative positional relationship between the predetermined position stored in the flash memory unit and the collection position of the light on light receiving unit.