To provide a lubricant feeding structure of a cam mechanism to continue a reliable feed of a lubricant for a long period.

A storage chamber 2a to store grease is formed on one end face side of a cam 2 and a grease pump 4 to feed grease is coupled to the storage chamber 2a through a connection pipe 5. A lubricant feed hole 2b which is communicated with a position on the outer peripheral surface of the cam 2 and through which grease in the storage chamber 2a is caused to flow out on the outer peripheral surface of the cam 2 is formed in a position closer to the lower part of the storage chamber 2a and an air intake hole 2c which is communicated with a position on the outer peripheral surface of the cam 2 and through which air is inputted from the external part to the interior of the storage chamber 2a is formed in a position closer to the upper part of the storage chamber 2a. This constitution causes grease gradually flows out through a lubricant feed hole 2b on the outer peripheral surface of the cam 2 under its gravity by feeding grease in the storage chamber 2a of the cam 2 to the interior of the storage chamber 2a through the working of the grease pump 4 and feeds it to the wholes of the outer peripheral surface of the cam 2 and a cam follower 3 by rolling the cam follower 3 over the outer peripheral surface of the cam 2.