To provide a compact angular adjustment device which can change a desired angle, is easy to operate, has little rattling,SOLUTION: This angle adjustment tool is an angle adjustment tool for restricting and releasing the axial rotation of the first member and the second member by reciprocating the locking body along the uniaxial center, When the locking body is moved forward, the concave and convex ridge along the axial direction provided in the truncated conical portion of the locking body, and the cone provided in the hole of the first member which can receive the truncated cone portion The engagement between the concavo-convex portion of the trapezoidal portion and the convex / concave portion engageable with the trapezoidal portion restricts the axial rotation of the first member and the second member, and when the engaging member is moved backward, the concave-convex portion And the convexo-concave portion provided in the hole portion of the first member are separated from each other, the regulation of the axial rotation between the first member and the second member is released.(FIG.【課題】本発明は、所望の角度変更が可能かつ操作が簡単で、ガタつきが少なく、コンパクトな角度調整具を提供する。【解決手段】本角度調整具は、一軸心に沿って係止体を往復移動させることで第1部材と第2部材との軸回転を規制及び規制解除する角度調整具であって、前記係止体を往移動させると、該係止体の円錐台形部に設けられたアキシャル方向に沿った凹凸条と、該円錐台形部を受容可能な第1部材の孔部に設けられた前記円錐台形部の凹凸条と係止可能な凸凹部と、が噛み合うことで前記第1部材と第2部材との軸回転を規制し、前記係止体を復移動させると前記円錐台形部の凹凸条と、前記第1部材の前記孔部に設けられた前記凸凹部と、が離間することで前記第1部材と第2部材との軸回転の規制が解除される。【選択図】図2