The hollow plunger of a hydraulic tensioner, slidably receives a sleeve that divides the high pressure oil chamber into two parts. The first part is formed by the plunger and a plunger-accommodating hole of the tensioner housing. The second part is formed by the plunger and the sleeve. Two springs, one being in the first part, and the other being in the second part, urge the plunger in the protruding direction. When the second part is filled with oil during ordinary engine operation, a negative pressure in the second part exerts a force opposing protruding movement of the plunger. Therefore, the springs can be made strong enough to prevent excessive chain vibration and noise during engine start-up when the parts of the high pressure oil chamber are not filled with oil, without causing the tensioner to exert excessive force on the chain during ordinary engine operation.