A wireless input apparatus includes a shell having a recess at a top surface thereof. The recess has an opening at a rear wall thereof. A bottom of the recess is formed with two abreast sliding slots which extend perpendicular to the rear wall. A stopper is disposed across each sliding slot and spaced from a rear side of the sliding slot to form a stopping recess. Each of two opposite lateral walls of the recess has a guiding trough. A rear side of the guiding trough has a buckling notch at a lower portion thereof. A wireless transmitter has a main body and an insertion portion protruded from a rear end of the main body. The main body has two lumps at a bottom thereof corresponding to the stopping recesses, and a pair of sliding pieces protruded outwards from two opposite sides thereof corresponding to the buckling notches.