PURPOSE: To obtain a differential thermal expansion measurement device with no degradation in measurement accuracy due to the self weight moment load on a sample pushing rod and the mechanism supporting the sample pushing rod.

CONSTITUTION: On a parallel motion mechanism 20 suspending a sample pushing rod with a pair of swing links 16, 17 parallel to each other on the same plane, a certain length arms 21, 22 perpendicular to the swing likes are fixed at one end as swing center of the swing links 16, 17. And both tips of the arms 21, 22 are connected with a tension spring 23. The spring characteristics of the tension spring 23 is set so that the moment load Mb incurred on the sample pushing rod by the tension spring 23 and the moment load Mw incurred on the sample pushing rod by the self weight of the mechanical parts.