An electrode sheet is capable of suppressing an influence of noise that is applied on a wire, and a biological signal measuring device uses the electrode sheet. The electrode sheet is provided with a sheet, a biological signal receiving electrode formed at the sheet and exposed from the sheet, a biological signal amplifier formed at the sheet, an interface part for connection to an external biological signal processing unit, a first wire that connects the biological signal receiving electrode and an input part of the biological signal amplifier to each other, and a second wire that connects the interface part and an output part of the biological signal amplifier to each other.