An engine device of including: an intake manifold configured to supply air into a cylinder; a gas injector configured to mix fuel gas with air supplied from the intake manifold, and supply mixed gas to the cylinder; an igniter configured to ignite, in the cylinder, premixed fuel obtained by pre-mixing the fuel gas with the air; and a control unit configured to execute a combustion control of a premixed fuel based on the output signal indicative of an output from the engine device. When the air amount is determined to be insufficient and when the output signal is lost, the control unit estimates an output signal based on the fuel gas injection amount from the gas injector, and executes the combustion control based on the estimated output signal.