The invention discloses a device for measuring the elementary gas outgassing rate of a material and a measurement method. The device and the method provided by the invention can measure the gas components released by the material to obtain the outgassing rate of various elementary gases released by the material and the total outgassing rate of the material, also the measurement device has the characteristics of simple structure, wide measurement range and small measurement uncertainty. The measurement device provided by the invention only adopts a sample chamber, an upstream chamber, a test chamber, a vacuum-pumping system, a standard leak, a mass spectrometer and a vacuum gauge to complete measurement of the solid material elementary gas outgassing rate. By using the method combining static constant volume boosting and dynamic continuous air pumping, the influence brought about by gas absorption to material outgassing measurement in a measurement process can be overcome, the measurement accuracy is high, the measurement uncertainty is small, and the measurement range is wide, the measurement lower limit of the material outgassing rate can be extended to the 10<-15>Pam<3>s<-1>cm<-2> magnitude.