We experimentally demonstrate that the Mosquito method is capable of fabricating polymer optical waveguides with extremely narrow pitch. The Mosquito method we developed recently is a technique for directly writing polymer waveguides with circular cores on a substrate using a microdispenser. Actually, even when parallel cores are formed by repetitive horizontal scans of a syringe needle with a 230-μm outer diameter, a pitch of 40 μm is achieved. It is noteworthy that the pitch is almost one third of the outer needle radius. For the waveguide fabrication, a silicone resin (FX-712 form ADEKA Corp.) is used for the core, which is a sufficiently durable polymer material. Furthermore, we also represent in this paper that a three-dimensional channel integration is also realized with the Mosquito method by varying the vertical position of the needle tip in the cladding layer. To the best of our knowledge, this paper is the first report of three-dimensionally aligned fan-out polymer waveguide realized with GI-circular-core including the pitch and core-height conversions.