万花尺 (日文：スピログラフ，俗称デザイン定规，英文：Spirograph，俗称Design Ruler) 是一种绘图玩具，由外图板及内圆图板两部分组成。内圆图板像一个齿轮，沿圆心不同半径的位置带有许多笔洞，外图板为一类似为内齿轮的大型圆孔，内圆板放在外图板的圆洞中，循着圆周转动，以铅笔或原子笔从笔洞可以画出像花朵一样规则图案。有些万花尺会配有几个不同半径的内圆图板。

万花尺所画出的图案，与外图板圆圈半径、内圆图板半径及笔洞位置有相关性。图案令人联想到万花筒，故名万花尺。

从数学(尤其是解析几何)观点观察，内圆板放在外图板的圆洞中，循着圆周转动所画出的图案是内旋轮线；两个内圆板互贴，固定其中一个内圆板，让另一个可活动内圆板沿着固定内圆板转动所画出的图案是外旋轮线；外图板为长方形之内挖出大圆孔，如果外图板的长方形外框上具有齿轮(一般没有，只有刻度供儿童当直尺使用)的话，内圆板沿着长方形外框转动所画出的图案是短摆线

Spirograph is a geometric drawing toy that produces mathematical roulette curves of the variety technically known as hypotrochoids and epitrochoids. It was developed by British engineer Denys Fisher and first sold in 1965.

The name has been a registered trademark of Hasbro Inc. since 1998 following purchase of the company that had acquired the Denys Fisher company. The Spirograph brand was relaunched with original product configurations in the USA in 2013 by Kahootz Toys and in Europe by Goldfish and Bison.