The invention provides a high-water level alarm device for a dishwasher and a dishwasher, and is used for solving the technical problem of high design complexity of a high-water level alarm structure in existing dishwasher. The dishwasher comprises a water softener, a washing chamber and an alarm device on the inner side of the bottom of a dishwasher outer shell, wherein the water softener is a thin integrated cavity vertically arranged between the washing chamber and the inner side of the dishwasher outer shell; a water outlet of the water softener is connected with a water inlet of the washing chamber through a connecting piece so that the water softener is communicated with the washing chamber; and a water overflow port is formed on the upper side of the water outlet of the water softener. When the water level in the washing chamber rises to a warning water level, the water level in the water softener cavity together rises to the water overflow port, the overflowing water flows to the dishwasher bottom from the water overflow port of the water softener cavity, and the alarm device is triggered to give an alarm; and in overall structural design, only a port is needed between the water softener and the washing chamber while the water softener and the washing chamber are communicated, the structural design is simple, and the design difficulty of the high-water level alarm structure of the dishwasher is reduced.