Chain drive device and chain guide

A chain drive device comprising:

• a chain having outer plates with a lower backside height than a backside height of inner plates;
• and
• a chain guide having a guide shoe that slidably guides the chain,
• the guide shoe including a shoe surface part that slidably guides the chain on an upper face thereof, and a lip formed on an outer side in a width direction of the shoe surface part and protruding upward from the shoe surface part,
• the shoe surface part having a larger widthwise dimension than a widthwise dimension of the chain,
• the lip having a front-side lip end on a front side in a chain running direction,
• the front-side lip end having a lip front end face as a flat surface that faces the front side in the chain running direction, and
• the lip front end face as the flat surface having a height that is set larger than a dimensional difference in backside height between the inner plates and the outer plates,
• the front-side lip end including an upper face slope extending from an upper edge of the lip front end face toward a rear side in the chain running direction,
• the upper face slope being slanted relative to a pitch line of the chain up toward the rear side, and the upper face slope having the height that is set larger than the dimensional difference in backside height between the inner plates and the outer plates, and
• a dimension of the upper face slope in the chain running direction being set shorter than a chain pitch.