To provide a gas adsorption measuring device capable of measuring, when measuring a gas adsorbed amount of a chemical compound, a large number of samples simultaneously by a series of operation to thereby rationalize the operation.

This device is provided with adsorption chambers into each of which a sample is inputted, an adsorption section having a plurality of adsorption chambers, an adsorption chamber selecting valve for selecting the absorption chamber, a gas reservoir, and a manifold led from the gas reservoir to the absorption chamber selecting valve, and a pressure converter communicated with the manifold. This device is preferably provided with a controller. A volume of the adsorption chamber is preferably larger than 100 times the total volume of the adsorption selecting valve and the manifold. The gas absorbed amount is measured by changing over the adsorption chamber selecting valve to select the adsorption chamber, allowing gas to be adsorbed to the sample inputted into the adsorption chamber, and causing the pressure converter to detect the pressure change of the gas.