Provided is a method of preparing a sample piece for a transmission electron microscope, the sample piece for a transmission electron microscope including a substantially planar finished surface which can be observed with the transmission electron microscope and a grabbing portion which microtweezers can grab without contacting the finished surface. The method of preparing a sample piece for a transmission electron microscope is characterized by including: a first step of cutting out the sample piece from a sample body Wa with a charged particle beam, the sample piece being coupled to the sample body at a coupling portion; a second step of grabbing with the microtweezers the grabbing portion of the sample piece with the finished surface of the sample piece cut out in the first step being covered with the microtweezers; a third step of detaching the sample piece grabbed with the microtweezers in the second step from the sample body by cutting the coupling portion with the charged particle beam with a grabbed state of the sample piece being maintained; and a fourth step of transferring and fixing with the microtweezers the sample piece detached in the third step onto a sample holder.