A personal data assistant (PDA) carrying case includes a main body (10), an expansion cover (40) having a first clasp (46) extending therefrom, a resilient clip (22) mounted on the main body, and a button (29). An opening (33) is defined in the main body for matching the expansion cover. A locking edge (36) is formed for engaging with the first clasp. A through hole (24) is defined in main body corresponding to the first clasp. The resilient clip has a projecting portion (222) corresponding to the through hole. The resilient clip deforms elastically to have the projecting portion pressing the button, so that the button drives the first clasp to disengage the first clasp from the locking edge of the main body.