A method for making an electronic switch mountable on a circuit board includes the steps of: (A) providing a housing that includes a base having opposite inner and outer sides, and a cover body having a main portion that cooperates with the inner side of the base to define a chamber, and an end portion that cooperates with the outer side of the base to define a sealing space; (B) providing a terminal having a connecting part extending through the base and the sealing space for connection with the circuit board; (C) providing the base with a hollow portion that projects outwardly from the outer side thereof into the sealing space and that confines an air-discharge hole communicating fluidly with the chamber; (D) providing a first adhesive layer to seal the sealing space without covering the air-discharge hole; and (E) sealing the air-discharge hole.