To finish washings hygienically than ever in an electric washer with an inner tank mounted inside an outer tank by minimizing the contamination of the washings by bacteria even when a closed space exists between an internal surface wall of the outer tank and an external surface wall of the inner tank to produce an environment, which promotes the breeding of the bacteria readily.

In an electric washer in which an inner tank 1 as rotating body is mounted inside an outer tank 2 as fixed body, (1) a copper material or a copper alloy material is applied at least on a part of an internal surface wall of the outer tank 2 or an external surface wall of the inner tank 1. (2) Alternatively, the inner tank is arranged free to be removed from the outer tank. The above-mentioned structure (1) may be combined with (2).