A connector has an inner housing with a cavity for housing a terminal fitting, an outer housing assembled displaceably to the inner housing and a rubber plug. The rubber plug has a sealing portion, a vibration reducing portion and a vibration absorbing portion. The sealing portion is mounted fixedly on a rear end portion of the terminal fitting and is brought into close contact with an inner peripheral surface of the cavity. The vibration reducing portion is fit in a holding hole formed in the outer housing and thus is displaced with the outer housing. The vibration absorbing portion has a smaller thickness than the vibration reducing portion and connects the sealing portion to the vibration reducing portion. The vibration absorbing portion is outside the holding hole and in front of the holding hole.