PURPOSE: To provide a writing implement which has an excellent function as a tool and is convenient and multi-functional.

CONSTITUTION: A ball-point pen A1 has a gripping axis 1, a housing axis 2, and a back axis 3. The gripping axis 1 is provided with an ink core 11, a helical part 12, and an engaging protrusion 13. The housing axis 2 is connected to the gripping axis 1. The housing axis 2 is made of a transparent plastic and has helical parts 21 and 22 on the inner periphery. The helical part 21 is connected to the helical part 12 helically, in which the ink core 11 is inserted and attached to the gripping axis 1. In the housing axis 2, an advertising barrel 4 is housed with the ink core 11 inserted therein. The advertising barrel 4 is made of a plastic coated with a luminous paint. On its peripheral face, advertising characters 40 are displayed, and an engaging recessed part 41 which engages with the engaging protrusion 13 is provided at an end. The back axis 3 is connected to the housing axis 2. A helical part 30 is provided on the outer periphery at the lower part of the back axis 3 and a push button 31 is provided at the upper part.