An attachable/detachable keyboard apparatus is provided for a portable multi-type computer system. The keyboard apparatus can be secured to an upper surface of main body of the computer system and selectively enable users to input data when the computer (e.g., web pad) is turned on. The keyboard apparatus can be used for a portable multi-type computer with web pad function and notebook personal computer in view that the keyboard apparatus can be easily attached to or detached from the main body of the computer system, thereby helping users to carry the computer more conveniently.