HIGH PRESSURE FUEL PUMP DEVICE

PROBLEM TO BE SOLVED: To provide a high pressure fuel pump device in which the durability of a bellows is improved by rationalizing the volume of a drain chamber and suppressing increase of pressure of the drain chamber in the neighborhood of the bellows. SOLUTION: This high pressure fuel pump device 200 is equipped with a fuel pressurizing chamber 45 formed of a sleeve 41 and a piston 43 inserted slidably in the sleeve 41 through a sliding clearance 45a for pressurizing fuel by volumetric change by the movement of the piston 43, a drain chamber 252 communicated with the sliding clearance 45a, collecting fuel leaked therefrom to be changed its volume by the movement of the piston 43, and a check valve 80 communicated with the drain chamber 252. The volume of the drain chamber 252 is small enough so that pressure change of fuel in the drain chamber 252 by volumetric change is propagated to the whole of the drain chamber 252. For example, the volume of the drain chamber 252 is less than 5 cm3. The channel cross sectional are of the drain chamber 252 may be formed into approximately the same over the whole length, or the housing passage part 252b of the drain chamber 252 may be formed into an uniformly thin cylindrical shape.