A housing assembly includes a first housing having first positioning holes, a second housing having second positioning holes, and an assembly unit connected between the first and second housings and including two assembly parts. Multiple engaging devices each include a first engaging member and a second engaging member. The engaging devices are connected to the first and second positioning holes by first and second resilient members. An operation device is connected to the engaging devices and includes first and second release members which are respectively connected to the assembly parts. A link is connected to the assembly unit and connected with the first and second release members. An operation member is connected to the link to move the first or second release members of each engaging device and disengage the first and second release members from the first or second positioning holes of the first or second housings.