An ambipolar dual-channel field-effect transistor (FET) with a WSe2 /MoS2 heterostructure formed by separately controlled individual channel layers is demonstrated. The FET shows a switchable ambipolar behavior with independent carrier transport of electrons and holes in the individual layers of MoS2 and WSe2 , respectively. Moreover, the photoresponse is studied at the heterointerface of the WSe2 /MoS2 dual-channel FET.