To prevent a foreign substance such as dust or a scale flowing into a liquid pumping device from being easily bitten into a space between a bearing part of a first spring bearing and a first shaft and a space between a bearing part of a second spring bearing and a second shaft.

A snap mechanism 5 is provided with: a rocking shaft 35 supported in a sealed vessel 2; a floating arm 34 and an auxiliary arm 37 rotating around the rocking shaft 35; the first shaft 39 supported to the floating arm; the second shaft 41 supported to the auxiliary arm 37; the first spring bearing 40 rotating around the first shaft 39; the second spring bearing 42 rotating around the second shaft 41; and a coil spring 38 mounted between the first and second bearing 40 and 42. A cross-sectionally U-shaped bearing part 46 is formed on the first spring bearing 40, and a cross-sectionally U-shaped bearing part 47 is formed on the second spring bearing 42.