A pellet 4 for use in spectrometry includes a first powder 41 of a light transmitting material in a compression-molded form, and a second powder 42 which is hydrophilic and water-insoluble and is dispersedly mixed in the first powder. A sample 40 to be subjected to spectrometry is e.g. in a powdery form and dispersedly mixed in the first and the second powders 41 and 42. When the sample 40 is a hydrate, the second powder 42 exerts the effect of accelerating dehydration of the sample 40, so that stable spectrum data on the sample in the dehydrated state is obtained early. This makes it possible to perform a processing such as identification of the sample 40 early and precisely.