Background: Equality of training opportunities and job satisfaction are not well studied among Japanese cardiologists, especially among female cardiologists in the invasive subspecialties. Methods: We investigated the career development of cardiologists using a questionnaire sent by e-mail to 14,798 cardiologists belonging to the JCS in September 2022. Feelings of equality in training opportunities and job satisfaction were assessed by examining cardiologists' age, gender and subspecialty. These feelings were compared between male and female cardiologists. Invasive treatment subspecialties included ischemia, arrhythmia, surgery, structural heart disease and emergency. Results: Responses were received from 2,566 cardiologists (17.3%). Female cardiologists (n = 624) were underrepresented in ischemia, cardiac surgery and emergency compared to male cardiologists (n = 1,942) (13.0% vs 29.5%, 2.4% vs 6.2%, 1.0% vs 3.2%, 1.4% vs 2.6%, respectively). Female cardiologists perceived more inequality in training opportunities than male cardiologists (44.1 vs. 33.9%, p=0.0001) and were less satisfied with their work than male cardiologists (71.3 vs 80.8%, p=0.0001). In the invasive subspecialties, female cardiologists felt more inequality than male cardiologists (50.0 vs 36.2%, p<0.001) and were less satisfied with their work than male cardiologists (74.0 vs 81.7%, p=0.001). Although male cardiologists in invasive subspecialties did not feel significantly more unequal and dissatisfied than those in non-invasive subspecialties (p=0.063, p=0.758, respectively), female cardiologists in invasive subspecialties felt more unequal and dissatisfied than those in non-invasive subspecialties (p=0.015, p=0.040, respectively). In invasive subspecialties, cardiologists with family care responsibilities were less satisfied with their work than cardiologists without those responsibilities (84.0% vs. 79.0%, p=0.039). Conclusions: Female cardiologists felt more inequality and dissatisfaction in career development than male cardiologists, especially in invasive subspecialties. Diverse workplaces can promote equality in training opportunities and job satisfaction for both female and male cardiologists.