A folding electronic device having a first housing and a second housing foldably connected through a hinge mechanism. The folding electronic device includes a first hinge cylinder integrated with the first housing, a second hinge cylinder integrated with the second housing, and a pipe inserted in one end of the first hinge cylinder and in one end of the second hinge cylinder to foldably connect the second housing to the first housing. The folding electronic device further includes a wiring member inserted through the pipe to connect a first electronic component mounted in the first housing and a second electronic component mounted in the second housing, a first gasket provided between the pipe and the first hinge cylinder, a second gasket provided between the pipe and the second hinge cylinder, and a hinge cap for tightly closing the other end of the first hinge cylinder