To provide a loupe suitable for enlarging and observing fish and the like in a water tank. A cylindrical loupe body (1) made of a material having flexibility and having substantially a truncated conical appearance and a cylindrical loupe body (1) having a substantially truncated conical appearance, And a convex lens 2 having an optical axis which coincides with the center axis of the cylindrical loupe body 1 and the position between the attachment position of the convex lens 2 and the upper end side opening 3 and the attachment position of the convex lens 2 At least one of the position between the lower end side opening 4 and the position of the lower end side opening 4 is provided with at least two thin portions 5 in which the thickness of the wall surface of the cylindrical loupe body 1 is reduced along the circumferential direction, Can be bent in a bellows shape at the position of the thin portion 5. (FIG.【課題】水槽内の魚等を拡大して観察するのに適したルーペを提供する。【解決手段】柔軟性を有する材質にて構成され、実質的に円錐台状の外観を有する筒状ルーペ本体1と、筒状ルーペ本体1の内部の上端側開口3と下端側開口4の間の位置に取り付けられ、当該筒状ルーペ本体1の中心軸と一致する光軸を有した凸レンズ2とからなり、凸レンズ2の取り付け位置と上端側開口3の間の位置及び、凸レンズ2の取り付け位置と下端側開口4の間の位置の少なくとも一方に、筒状ルーペ本体1の壁面厚みが薄くなった薄肉部5が周方向に沿って少なくとも2箇所設けられており、筒状ルーペ本体1の壁面が、薄肉部5の位置で蛇腹状に折り曲げ可能になっている。【選択図】図1
