An ionic liquid is utilized as the dynamic-pressure fluid charged inside a bearing space formed in the gap where an axial bushing (axial component) [21] and a bearing sleeve (bearing component) [13] oppose. Designing a dynamic-pressure bearing device is made possible virtually without having to consider such factors as how to control dynamic-pressure-fluid evaporation or how to secure electrical continuity between the axial bushing and the bearing sleeve. Owing to ionic liquids' property of not hydrolyzing, deterioration of the dynamic-pressure fluid from moisture absorption, oxidation, etc. is inhibited, yielding a dynamic-pressure bearing device with a long lifespan.