To provide a portable spherical-object measuring device, which accurately measures the diameter of a spherical object.

There are provided a first support arm 12 whose one end 22 is made to contact one spherical part in a line 24 running the diameter of a ball 20 while whose the other end is made to face the other spherical part on the line 24 passing through the diameter with an interval, a second support arm 14, which is provided orthogonal to the first support arm 12 and whose end 40 is made to contact a spherical part on a line 42 passing through the radius orthogonal to the line 24 running the diameter, and a dial gauge 16, which is provided at the other end 28 of the first support arm 12, made to contact the other spherical part on the line 24 passing through the diameter.