Abstract: The present invention relates to a fixing apparatus for a mounting type card member which is capable of implementing an easier installation of an option card in a computer main chassis without using any tools. In the computer casing, there are provided a main chassis having a bracket having a fixing portion, and a motherboard engaged to the main chassis and having one or more slots, the card members having a connector portion connected with the slot and a bracket formed at one end of the same. A fixing member has a body portion which supports the card member bracket and fixing portions formed at both ends of the body portion, whereby the fixing portions are fixed to the fixing portion of the main chassis, and the body portion contacts with the bracket of the card members for thereby preventing a movement or escape of the card members.