An image forming apparatus has a vibration generating source, a holding member that holds the vibration generating source and a sealing member arranged between them. An elastic damping member is inserted in a through-hold formed in the holding member and is brought into pressure contact with the vibration generating source, the damping member having a retaining portion which is retained to a surface of the holding member on the side opposite to a holding surface of the vibration generating source and a main body portion that has a diameter smaller than a diameter of the through-hole so that it is inserted into the through-hole without contacting the through-hole and brought into pressure contact with the vibration generating source. There is also a fixing portion that integrally fixes the holding member and the vibration generating source through the damping member.