A biological information detection device includes a main body portion, a heartbeat detection portion, forced integrally with the main, body portion, which has electrodes that come into contact with a biological surface, and a fixing band, detachably provided to the main body portion, which mounts the main body portion and the heartbeat detection portion to a user. A sealing portion for securing sealing of an electrical connection portion is provided in the periphery of the electrical connection portion that electrically connects the main body portion to the electrodes of the heartbeat detection portion.
