NOVELTY - The method involves preparing (GG) a first liquid so that the ultrapure water is distributed to a first catalyst-precursor for electrodes. The ultrapure water is used so that the catalyst-precursor for electrodes contained in first liquid is filtrate-washed (HH) and repeated until the electric conductivity measured by Japanese industrial standard testing method (JIS K0552) of a filtrate obtained is preset below the first setting value. The second catalyst-precursor for electrodes is distributed to ultrapure water, and the second liquid is prepared (JJ).    USE - Method for manufacturing catalyst for electrode such as gas-diffusion-electrode of membrane/electrode joined case (MEA) used in fuel cell stack (all claimed) and electrical machinery apparatus industries such as fuel cell, fuel cell electric vehicle, portable mobile, but enefarm, and cogeneration system.    ADVANTAGE - The ultrapure water is used so that the catalyst-precursor for electrodes contained in first liquid is filtrate-washed and repeated until the electric conductivity measured by testing method of JIS K0552 of filtrate obtained is preset below the first setting value and second catalyst-precursor for electrodes is distributed to ultrapure water, and the second liquid is prepared so that the comparatively low concentration at ultrapure water is wash-removed easily in conditions even when the acid is used. Thus, the content of chlorine species acquired in the catalyst for electrodes is reduced reliably by simple operation. Hence, the catalyst for electrodes is manufactured easily in mass at reduced cost while preventing the catalyst active fall generated under the influence of chlorine species about the catalyst for electrodes on clean conditions without using the reagent for removing chlorine.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a composition for gas-diffusion-electrode formation; and    (2) a fuel cell stack.    DESCRIPTION OF DRAWING(S) - The drawing shows a flowchart illustrating the process of manufacturing catalyst for electrode. (Drawing includes non-English language text)    Step for performing pre-processing process (BB)    Step for preparing first liquid (GG)    Step for washing filtrate of catalyst-precursor for electrodes contained in first liquid (HH)    Step for preparing second liquid (JJ)    Step for performing drying operation (KK)