This study is to evaluate the impact of cooperation between acute care hospital and rehabilitation hospital on physical function, exercise tolerance, activities of daily living (ADL), health-related quality of life (HR-QOL), and psychological function in heart disease patients undergoing cardiac rehabilitation. Among patients undergoing concurrent medical treatment and cardiac rehabilitation starting early in acute care hospitalization, we selected 30 patients who required continued cardiac rehabilitation in rehabilitation hospitals as subjects. At the time of admission and discharge from the rehabilitation hospital, we measured and compared physical function [grip strength, knee extension strength, and the short physical performance battery (SPPB)], ADL ability using the Functional Independence Measure (FIM), exercise tolerance [six-minute walking distance (6MD)], and psychological functions such as the MOS 36-Item Short-Form Health Survey (SF-36). The average age of the subjects was 76.8 years and 60% were women. In 70% of cases, musculoskeletal causes were the reasons for continued cardiac rehabilitation in a rehabilitation hospital. In evaluations before and after hospitalization, significant improvements were observed in knee extension strength and the results of the SPPB (p < 0.01), FIM, and 6MD (p < 0.01). In SF-36, significant improvements were observed in physical function, role functioning, vitality, and emotional functioning (p < 0.05, p < 0.01). With intensive cardiac rehabilitation in rehabilitation hospitals, physical function, ADL, exercise tolerance, and HR-QOL improved significantly. As the severity and prevalence of heart disease are expected to increase in association with multiple disabilities and aging, the importance of cooperation between acute care hospitals and rehabilitation hospitals will increase; therefore, cardiac rehabilitation should be the basis for such cooperation.