Bacillus cereus is a gram-positive rod-type bacterium that forms endospores and is distributed throughout various environments. It rarely causes disease in humans except for cases of food poisoning. However, infection with B. cereus in newborns and immunocompromised individuals can cause severe sepsis. Inappropriate catheter insertion and environmental contamination, including that of linen, are thought to be routes of transmission. Pseudo-outbreaks of B. cereus caused by poor hospital linen management have been reported and are important issues in hospitals. The number of Bacillus spp.-positive blood culture specimens increased in "A" ward of our hospital. Consequently, the hospital's infection control team was asked to determine the cause of the increase. We performed environmental research in the "A" ward and the entire hospital. In addition, we investigated the current status of B. cereus derection in five core hospitals in the North Tohoku region. In our hospital, B. cereus was detected in towels before use. When the timeline of contamination was investigated, we found that the towels had already been contaminated at the time they were delivered to our hospital. The linen washing contractor was unconcerned with laundry disinfection. As a result of our findings, disposable towels were introduced. This resulted in a decrease in Bacillus spp.-positive blood culture specimens. Among the five core hospitals in the North Tohoku region, the hospitals outsourcing laundry to contractors without bacteriological monitoring had a significantly higher rate of B. cereus-positive blood cultures than those of three other hospitals with infection control policies for towel management. The increase in Bacillus spp.-positive blood culture specimens in our hospital was a result of towel contamination. Based on these findings, we suggest that proper linen management(including that of towels) is crucial for infection control as well as the quality control of bacteriological tests.