The present invention relates to a patch type thermometer containing a polymer that can be phase changed from a solid phase to a liquid phase. The patch type thermometer provided in an aspect of the present invention demonstrates high precision since it does not include conductive particles which have been a reason of disadvantage of the conventional temperature sensor, and has the effect of no temperature deviation in repeated temperature measurements because it is composed of such a single polymer material that is phase changed in a specific temperature range so that the polymer material can be reversibly changed in the volume and shape.