The vapor permeability, equilibrium moisture content, hydraulic conductivity, and thermal conductivity of concrete specimens with three different strengths were measured under various conditions of temperature and relative humidity. Based on the measured results, the relationship between hygrothermal properties and strength, and the relationship between hygrothermal properties, water content, and temperature were considered. The variability of measured hygrothermal properties was clarified. Then, to evaluate the influence that the variability of hygrothermal properties has on the hygrothermal behaviors of a concrete wall, a water absorption experiment using a small-scale concrete wall with tile finishing was carried out under constant temperature. The experimental result shows a significantly difference between three specimens in the hygrothermal behaviors, which is partly because of the variability of the hygrothermal properties.