Fuel pump driving structure and internal combustion engine

A fuel pump driving structure configured to drive a high-pressure fuel pump of an internal combustion engine, the fuel pump driving structure comprising:

• a camshaft configured and arranged to be rotatably supported at an end by a cylinder head of the internal combustion engine;
• and
• a pump cam member having an internal circumference surface defining a fitting hole into which the end of the camshaft is press fitted, and configured to be operatively coupled to the high-pressure fuel pump to drive the high-pressure fuel pump, the pump cam member including
• a pump cam section having a first lift portion configured to operate the high-pressure fuel pump, and a base circular portion configured so as to not operate the high-pressure fuel pump, and
• a first contact section arranged in a position offset from a position of the first lift portion with respect to a circumferential direction, and contacting a portion of the camshaft in an axial direction of the camshaft at a position radially outward of an external circumferential surface of the one end of the camshaft so as to reduce bending of the camshaft where the pump cam member is mounted.