Abstract: A tact switch (1) includes a housing (10) defining a cavity (1000) in a middle thereof, a first contact (11) and a second contact (12) received in a portion of the housing under the cavity, a dome-shaped metal spring (13) mounted in the cavity, a seal pad (14) mounted on a top of the housing, a metal shell (15) covering the housing, and a push button (16) engaging with the shell and attached on the seal pad. The shell comprises a base portion (153), and three sidewalls (151) and a tab (152) respectively perpendicularly depending from edges of the base portion. The seal pad is substantially rectangular, and frictionally fitted between two opposite of the sidewalls and the tab at an underside of the base portion. Therefore, the seal pad is securely retained in a correct position in the shell in assembling.