An auxiliary input device for virtual keyboard sized on a displayed virtual keyboard of a capacitive touch panel, comprising: a membrane and a plurality of conducting keys. The membrane has a plurality of bulged supporting members arranged in correspondence to the plurality of virtual keys of the virtual keyboard, wherein a trough is arranged facing the virtual keyboard between every two adjacent supporting members. The conducting keys are arranged atop each of the supporting member, and kept at a predetermined distance from the capacitive touch panel, the conducting keys selectively operable to establish contact with the capacitive touch panel. The auxiliary input device for virtual keyboard is a thin structure which provides tactile feedback and pressure-sensitivity just like a physical keyboard, and is advantageous in its low cost construction, easy portability and the lack of additional power consumption.