This study explores factors related to delayed emergency medical treatment for acute myocardial infarction patients on Kinmen Island. A cross-sectional study was performed in the only hospital in Kinmen Island. The study group consisted of 116 patients diagnosed with acute myocardial infarction (AMI, ICD-10 codes: 121.9) from November 2015 to May 2019. The binary logistic regression analyses were performed for the inferential statistical analysis. The mean age of the study group was 63.0 ± 14.5 years, 39.7% of the patients arrived at the emergency medicine longer than 6 h after the onset of symptoms. The related factors for delayed arrival the hospital emergency medicine department were female sex, age over 65 years, less than nine years’ education, and Killip Class, but only Killip Class reached the significant difference of statistics (OR = 3.616, 95% C.I. = 1.574 to 8.310, p = 0.002), and patients with delayed arrival times (>6 h) were found to have a higher percentage of Killip Class ≥ II. Therefore, it is essential to remind the physicians to proceed with risk stratification for acute coronary syndrome patients. In addition, health authorities should provide effective programs to increase awareness of the symptoms and timely treatment of acute myocardial infraction to the general public, especially the elderly.