A vibration damping device (1, 10, 100) includes a tubular metal bracket (20, 120), a first attachment member (12, 112), a second attachment member (11, 23, 111), an elastic body (13, 113), a partition member (17, 117), and a diaphragm (19, 119). A fixed portion (11g, 23c, 111c) fixed to a fixing portion (20b, 120b) of the metal bracket is formed in the second attachment member. A gap (S2, S21) is provided between a portion of an outer circumferential surface of the second attachment member except for the fixed portion, and a portion of an inner circumferential surface of the metal bracket except for the fixing portion, and a second seal portion (22, 123) is provided between the fixed portion and the fixing portion.