The cultivar cannabis (Cannabis sativa L.) ‘Tochigi-shiro’ has been developed by the Tochigi Prefectural Institute of Public Health and Environmental Science and Tochigi Prefectural Agricultural Experiment Station. It is considered nontoxic and a fiber-type cannabis because of its low concentration of the hallucinogen Δ⁹-tetrahydrocannabinol (THC). Recently, concentrated forms of cannabis, such as butane hash oil (BHO), have spread globally, and seizures of BHO have increased in Japan. We expect that the use of BHO prepared from Tochigi-shiro may be detrimental to health. However, the concentrations of cannabinoids in Tochigi-shiro have not previously been reported. In this study, the concentrations of THC, cannabidiol (CBD), cannabinol, and tetrahydrocannabivarin in Tochigi-shiro cultivated in Tochigi Prefecture were measured. Further, BHO was produced from the leaves of Tochigi-shiro using commercially available extraction devices to determine the extraction efficiency of THC and CBD. THC was detected in Tochigi-shiro, and concentrations of each cannabinoid differed between plants grown at three sites in Tochigi Prefecture. However, the concentration ratio of CBD to THC was almost the same in plants from all three sites. In BHO, the concentrations of THC and CBD were 6.59% w/w and 35.0% w/w, respectively. This indicates that the concentrations of THC and CBD were approximately 55- and 35-fold greater, respectively, in BHO than in the leaves of plants before butane gas extraction. We confirmed that the concentration of THC in plants was low, whereas the concentration in BHO was high. In the BHO manufactured from Tochigi-shiro, the CBD concentration was five times higher than that of THC. Moreover, CBD can antagonize the psychotomimetic symptoms caused by THC. Therefore, even if BHO produced from this plant was used, the effect of THC would hardly be obtained. Currently, interest in cannabis is increasing worldwide. The traditional industry producing cannabis as a source of fiber may be affected by the theft of Tochigi-shiro. The results of the present study are relevant to prefectural and city governments and cultivators, and suggest the need for additional protection of cultivated fields against theft.