To determine a correct reduction rate of an overall heat transfer quantity by calculating a heat quantity load finely to conform to the reality.

There is provided the method for measuring effects of the heat shield paint. According to the method, after a color of the paint is determined, a solar factor defined by JIS A5759 of this paint is measured, and a solar absorptance is calculated from the measured solar factor. An equivalent ambient temperature is calculated on the basis of the solar absorptance by an equation A of the equivalent ambient temperature = a temperature + a solar radiation × the solar absorptance/20. Moreover, a break-through heat quantity is calculated by an equation B of the break-through heat quantity = a K value × an area × (the equivalent ambient temperature - a room temperature) wherein the K value (thermal resistance) is an overall heat transfer coefficient of a material to be painted.