A mouse housing structure includes a housing having a main body of a front wall, and a tongue portion defining a position wall, at least a track device disposed at the tongue portion and defining first and second position ends at two opposite ends thereof, and a sliding device including a sliding body and at least a rotatable shaft having first and second engaging portions. The first engaging portion is movably and rotatably disposed in the track device, and the second engaging portion is spaced away from the track device for pivotally engaging with a coupling slot of the sliding body. When the sliding body moves forwards to where the first engaging portion slides against the first position end, the sliding body rotates towards the position wall, and is restrained by the position wall so as to expand the mouse housing structure for use.