A lubricating mechanism of a multilink, piston-crank mechanism for an internal combustion engine is provided. At a predetermined crank angle at which the crank pin oil passage and the lower link oil passage are communicative, viewed in the direction of the crankshaft, along a straight line connecting the center of rotation of the crank shaft and the end of the lower link oil passage at the side opposed to the pin boss opposing surface, the pin boss portion is disposed as the lubricating object. On the axial side of the pin boss portion, a recess portion is provided.