Objective：The previous study was to develop the“Itamikei”, a small machine which patients can use to record their subjective level of pain. And new assessment tool“Tablet PC application for Pain Memory”, which enable the user to visualize and record the pain levels both instantly and over time. The purpose of this study was to examine the effectiveness of Pain Memory as a pain assessment tool for patients with cancer pain. Method：12 inpatients prescribed analgesics for cancer pain, were instructed to input their pain level into Pain Memory over a 2-week period, and the resulting graph was reviewed by the patient and staff. They also completed a questionnaire evaluating the design, function and pain assessment of the tool. Result：The patients input their pain level into Pain Memory 5.25 times／day（Md）, which provided increased opportunities to ascertain the patient’s pain level compared to that“Itamikei”. The design and function of the Pain Memory were given approximately rate 4 using a 5 point scale by both patients and staff members. Moreover, using Pain Memory, the patients highly rated the parameter“I understood changes in pain”, and the staff members highly rated the parameter“Patients participating in the treatment of pain”. Conclusion：We found Pain Memory could be useful in the assessment of pain. It provided more opportunities to ascertain the pain level of patients, and enabled the visualization of the pain level through a graph.