The check valve unit of a hydraulic tensioner comprises a check ball, a ball guide and a disc-shaped retainer. The retainer is fixed to the high pressure oil chamber side of the ball guide by crimping an annular portion of the ball guide over the outer edge of the retainer so that substantially all of an annular circumferential portion of the high pressure chamber side of the retainer is held underneath the crimped portion of the ball guide. The crimped portion of the ball guide forms a recess for receiving and positioning a plunger-biasing spring. A ball seat is similarly secured to the inflow side of the ball guide by crimping.