A waterproof electrical connector for electrically connecting wiring to a mating connector having a concavity, the waterproof electrical connector having a contact connected to an end of a wire, a housing having a fitting section configured to at least partially house the contact and configured for insertion into the concavity, a seal integrally arranged on an outer periphery surface near a top end of the fitting section, which sealingly contacts an inner wall of the concavity when the fitting section is inserted into the concavity, and a lock which prevents the housing from exiting the concavity once the fitting section has been inserted into concavity to a predetermined depth is disclosed.