Provided is a substrate for transferring microstructures such as a micro LED including an engraved mark. The substrate for transferring microstructures is less likely to cause a recognizing error of the engraved mark to occur in a reading device, and makes it possible to stably and continuously read the engraved mark. A substrate for transferring microstructures includes a synthetic quartz glass substrate and a silicone pressure-sensitive adhesive agent layer provided on a front surface of the synthetic quartz glass substrate. The substrate includes an engraved mark provided in the from surface.