Abstract: Provided is a chemical analysis device to analyze a chemical composition of a sample, including a main body including a laser light source, a chemical analysis unit, and a housing; an optical head that is arranged to be faced to the sample; and a pressureproof-feedthrough-equipped fiber that is extended from the housing to the optical head to guide laser light emitted from the laser light source to the optical head. The housing houses the laser light source and the chemical analysis unit as having a pressure-resistant function. The optical head includes a mirror system that causes the sample to be irradiated with laser light outgoing from the pressureproof-feedthrough-equipped fiber and to cause plasma emission light occurring at the sample owing to irradiation with the laser light to reenter to the pressureproof-feedthrough-equipped fiber. The chemical analysis unit performs spectroscopic analysis on the plasma emission light that reentered to the pressureproof-feedthrough-equipped fiber.