Abstract: A case for a bar type mobile electronic device is provided. The case includes a main body and an auxiliary body. The main body includes a periphery part and guide parts. The periphery part wraps the sides of the mobile electronic device. The guide parts cover parts of the front and back of the mobile electronic device. The guide parts are extended in the direction where the mobile electronic device is located at both opposite edges of the periphery part. The auxiliary body wraps the outer surface of the periphery part. The auxiliary body applies pressure to the main body in the direction of the mobile electronic device. The auxiliary body assists the main body to couple to the mobile electronic device, so that the case cannot be easily removed from the mobile electronic device and can protect the mobile electronic device from scratches and external impact.