A fixing-device that fixes a second member to be fastened to a first member to be fastened, the fixing-device includes, a base fixed to the first member to be fastened, a sprung-washer attached to the base and interposed between the base and the second member to be fastened, and a fastener that fastens the second member to be fastened and the base to each other, wherein the sprung-washer includes a threaded-portion insertion-hole into which a threaded-portion of the fastener is inserted, an edge-portion that is formed around the threaded-portion insertion-hole, and with which a pressing-portion provided in the fastener comes into contact and that is thereby pressed when the fastener is tightened, and a leaf-spring that extends from the edge-portion forward in a direction in which the fastener is inserted into the threaded-portion insertion-hole and outward, and that has a bent-portion midway along the length of the leaf-spring.