A computer case for installing computer parts such as a motherboard therein is provided. Two casings (including a first casing and a second casing) of the same size, specification and type are assembled opposite to each other to form a complete case. In this way, the manufacturing cost can be greatly saved, and the finished product can be further equipped with panels or baffle plates of different specifications or types according to user requirements, so as to meet the manufacturing requirements for high customization.