This paper presents the research on the expanding characteristic of zeolite rock (Ohya-Rock) and the fundemental properties of aggregate and concrete with expanded zeolite rock as a structural lightweight concrete. We received a few beneficial conclusions in this investigation. (1) We could produce a new type of artificial lighweight aggregate that is made of zeolite rock crushed and fired at about 1250℃. (2) This artificial lightweight aggregate has many pores that are not connected to each other. Therefore, this aggregate has a higher compressive strength than the other artificial lightweight aggregates, and the water absorption is not as high as in the other aggregates. (3) The compressive strength of the concrete mixed with expanded zeolite aggregate is higher than the other concretes composed of expanded clay aggregate and expanded slate aggregate. From the above results, we can conclude that the expanded zeolite aggregate is the most qualitified as a structural lightweight concrete aggregate.