A sealing device which can stably exhibit a sealing function and enables a reduction in the number of components as well as in a radial size of the device. The sealing device includes a metal cartridge case (110) having a case main body (111) and a first supporting portion (113), a resin sealing member (120), an elastic sealing member (130), and a metal fixing member (140). An outer diameter of a cylindrical portion (141) of the fixing member (140) is set to be equal to or smaller than an inner diameter of the case main body (111), and the cylindrical portion (141) and the case main body (111) are secured by welding. The resin sealing member (120) and the elastic sealing member (130) are fixed by being held in between the first supporting portion (113) and a second supporting portion (142) of the fixing member (140).