An embedded measurement device that is capable of measuring the component and a composition of a multi-phase flow fluid flowing in a pipe. The embedded measurement device includes: a high-pressure pipe tube in which the multi-phase flow fluid flows; a Raman probe that is partially inserted inside the high-pressure pipe tube and has an optical lens; and a Raman peak analysis unit that is connected to another part of the Raman probe. The device for measuring the composition of the multi-phase flow fluid measures a Raman peak intensity value of the multi-phase flow fluid in the high-pressure pipe tube by using the Raman probe, thereby determining the composition of the fluid.