of the operating portion 9 there are provided two attaching protrusions 13 in a back and forth direction the operating portion 9 is attached to the reservoir tube 5 by fitting the attaching protrusions 13 to fitting holes 14 of an operating portion attaching piece 8 see fig2 in the reservoir tube 5 in respective surfaces of the three operating portions 9 convex portions are provided namely a single central protrusion 16 of essentially triangle shape in side view is provided on a first operating portion 9 a two protrusions 17 of a same triangle shape are provided spaced from each other in the back and forth direction on a second operating portion 9 b and a single central protrusion 18 of trapezoid shape in side view is provided on a third operating portion 9 c in this manner by mutually differentiating the numbers or shapes of the protrusions 16 17 and 18 of the operating portions 9 a 9 b and 9 c of the reservoir tubes 5 different in writing colors the desired writing color can be easily selected even in a gloomy place or by even a person with poor eyesight owing to the different touch feelings in operating the operating portions 9 a 9 b and 9 c by a finger e g thumb of a hand to thereby allow it to be used fig5 and fig6 are views showing another embodiment and corresponding to fig4 in this embodiment a first ballpoint pen having operating portions 19 a 19 b and 19 c shown in fig5 and a second ballpoint pen having operating portions 20 a 20 b and 20 c shown.