A float switch, including a junction box, a switch, a guide rod, a float, a link mechanism, and a seal assembly. The switch is disposed in the junction box. The junction box is tightly coupled to the link mechanism. The float is flexibly disposed on the guide rod. The link mechanism includes a sealing member, a cylindrical pin, a connecting rod, a support, and a shift fork; one end of the link mechanism is connected to the switch via the shift fork, and the other end of the link mechanism is connected to the guide rod. The support includes a first through hole and a second through hole which are perpendicular to one another. The connecting rod includes a through hole corresponding to the second through hole of the support. The connecting rod runs through the first through hole of the support.