OBJECTTo provide a hydraulic lash adjuster capable of retaining a large amount of hydraulic oil, in a reservoir communicated with a high-pressure chamber when the engine is stopped.MEANS FOR SOLVING THE PROBLEMA hydraulic lash adjuster including: a cylindrical body (24) having an upper open end, a closed bottom, and a second
oil supply hole (27a) formed in the sidewall of the cylindrical body; and a
plunger having a top end serving as a plunging end, a sidewall, a bottom end, a
high pressure chamber (29) at the lower bottom, and a first
oil supply hole (24b) formed in the sidewall, the
plunger being slidable on the inner wall of the body. The
plunger has a reservoir (28) that communicates with an external
oil supply line (32) via the first oil supply hole (24b) and the second oil supply hole (27a). The lash adjuster is provided with a
check valve (40a) for opening the oil supply hole (24b) by the
oil pressure led from an external oil passage (32) to the oil supply hole (24b). The
check valve (40a) is arranged in an annular communication passage (T) formed between the sidewalls of the plunger (26) and the body (24) for communicating the oil supply hole (27a) with the oil supply hole (24b). Leak-down oil is recycled while the engine is in operation. When the engine is stopped, the
check valve (40A) closes the oil supply hole (24b). Accordingly, a large amount of hydraulic oil is stored in the reservoir (28) communicated with the
high pressure chamber (29), with the oil level H in the reservoir (28) never being lower than the open end of the body (24).