A mixed code, and a method and apparatus for encoding the same are provided. The mixed code includes a first code image region storing a first code image obtained by encoding first information using color, shading, or a combination thereof, and a second code image region storing a second code image obtained by encoding second information using color, shading, or a combination thereof. The first code image and/or the second code image includes the results of encoding interpretation information, construction information, error control information, and code direction information. The mixed code is made by adjusting the difference in color and brightness between the first and second code images to a predetermined level and combining these images.