A small portable surveyor, easy to use, was newly devised. The surveyor is essentially a parallelometer, an instrument used for determining the relative parallelism of two or more surfaces of the teeth or other parts of the dental cast. The characteristic structures of this instrument is as follows: The vertical standard is directly connected to the cast table with a universal joint, different from the others, and it can be tilted in any given degree to the table. The vertical sliding spindle can move freely parallel to the standard with the two horizontal arms, and it carries pencil leads of 0.9mm phi inside just as a mechanical pencil in structure. The accuracy of this surveyor is thought to be equal to that of the conventional ones in ordinary use.