Binding energy between a vacancy and a Zn atom in Al was investigated by measurement of as-quenched resistivity in Al-0.021at % Zn and pure-Al, with the estimation of vacancy loss during quenching. The contribution of clusters to resistivity in Al-0.021at % Zn waa also investigated. Their results are summarized as follows: (1) The results of isothermal and isochronal annealing indicate that clusters in Al-0.021at % Zn cnuld not be detected beyond the experimental errors. (2) The model applied to estimate the vacancy loss in pure-Al has enough validity. The quantitative estimation of clusters ana the improvement in experimental conditions are greatly desired, which enable the more detailed, analysis of the data.