An engine unit (100,101) comprising: a four-stroke engine body including a combustion chamber having an intake port and an exhaust port, an intake valve configured to open and close the intake port, an exhaust valve configured to open and close the exhaust port, an intake passage connected to the intake port and configured to guide air in the atmosphere into the combustion chamber through the intake port, an exhaust passage connected to the exhaust port, a fuel injection device configured to inject fuel into the intake passage, an ignition device configured to ignite an air-fuel mixture including fuel and air in the combustion chamber, a piston configured to move to and fro in the combustion chamber, and a crank shaft connected to the piston to rotate in accordance with the to-and-fro movement of the piston, wherein a high-load region where a load for rotating the crank shaft is high and a low-load region where a load for rotating the crank shaft is lower than the load in the high-load region being present in four strokes; a permanent magnet starter motor that includes a permanent magnet and is configured to rotate the crank shaft; a control device that is configured to control the permanent magnet starter motor, the fuel injection device, and the ignition device; an engine temperature detector that is configured to detect a temperature of the four-stroke engine body; and a crank angle detector that is configured to detect a crank angle, the crank angle being a position of a rotation angle of the crank shaft, wherein the control device is configured to drive the permanent magnet starter motor to rotate the crank shaft from a suspended state, control the fuel injection device while a crank angle of the crank shaft is in the low-load region, thereby injecting fuel into the intake passage, control a rotation speed of the permanent magnet starter motor so that an increase in a rotation speed of the crank shaft is suppressed and the time for vaporization of fuel is obtained, based on the temperature of the four-stroke engine body detected by the engine temperature detector while the crank angle of the crank shaft is in the low-load region and from when the fuel injection device injects fuel into the intake passage to when the intake valve is closed, and start the four-stroke engine body by igniting the air-fuel mixture in the combustion chamber by using the ignition device while the crank angle of the crank shaft is in the high-load region. a four-stroke engine body including a combustion chamber having an intake port and an exhaust port, an intake valve configured to open and close the intake port, an exhaust valve configured to open and close the exhaust port, an intake passage connected to the intake port and configured to guide air in the atmosphere into the combustion chamber through the intake port, an exhaust passage connected to the exhaust port, a fuel injection device configured to inject fuel into the intake passage, an ignition device configured to ignite an air-fuel mixture including fuel and air in the combustion chamber, a piston configured to move to and fro in the combustion chamber, and a crank shaft connected to the piston to rotate in accordance with the to-and-fro movement of the piston, wherein a high-load region where a load for rotating the crank shaft is high and a low-load region where a load for rotating the crank shaft is lower than the load in the high-load region being present in four strokes; a permanent magnet starter motor that includes a permanent magnet and is configured to rotate the crank shaft; a control device that is configured to control the permanent magnet starter motor, the fuel injection device, and the ignition device; an engine temperature detector that is configured to detect a temperature of the four-stroke engine body; and a crank angle detector that is configured to detect a crank angle, the crank angle being a position of a rotation angle of the crank shaft, wherein the control device is configured to drive the permanent magnet starter motor to rotate the crank shaft from a suspended state, control the fuel injection device while a crank angle of the crank shaft is in the low-load region, thereby injecting fuel into the intake passage, control a rotation speed of the permanent magnet starter motor so that an increase in a rotation speed of the crank shaft is suppressed and the time for vaporization of fuel is obtained, based on the temperature of the four-stroke engine body detected by the engine temperature detector while the crank angle of the crank shaft is in the low-load region and from when the fuel injection device injects fuel into the intake passage to when the intake valve is closed, and start the four-stroke engine body by igniting the air-fuel mixture in the combustion chamber by using the ignition device while the crank angle of the crank shaft is in the high-load region.