Provided is a putter in golf clubs for use in swinging and putting beside a golf ball while looking at front and keep watching the moving trace of the golf ball, which is titled as a look & watching side swing putter by which a golfer stands at the same point of place where he examined the green grass state and the distance previously, and practices swings while checking the estimated imaginary putting line of the golf ball, and executes putting of the golf ball on the side thereof like bowling while keep watching the golf ball, thereby reducing the putting errors or strokes to wrong directions due to the differences in views direction depending on putting posture and improving straight-line movement of the golf ball at putting.