An internal combustion engine includes a main combustion chamber, an auxiliary combustion chamber, a fuel reforming unit, and a control unit. The auxiliary combustion chamber is configured and arranged to communicate with the main combustion chamber. The fuel reforming unit is configured and arranged to reform a fuel to produce a reformed gaseous fuel and a reformed liquid fuel. The control unit is configured to execute control such that the reformed gaseous fuel is supplied to the auxiliary combustion chamber when a first operating condition exists and the reformed liquid fuel is supplied to the main combustion chamber when a second operating condition exists.