INTERNAL COMBUSTION ENGINE

The internal combustion engine includes a second separator, a connection pipe, and a pressure sensor. Inside the second separator, a main chamber located in the cylinder head cover, and a first sub-chamber and a second sub-chamber located in a joint portion located outside the cylinder head cover are formed. The first sub-chamber and the second sub-chamber are partitioned by partition walls. A communication hole connecting the first sub-chamber and the second sub-chamber is formed in the partition wall. The first sub-chamber is connected to the main chamber via a throttle portion. A first connection port connected to the first sub-chamber and a second connection port connected to the second sub-chamber are formed in the joint portion. The first connection port is connected to the intake passage via a connection pipe. The second connection port is connected to the pressure sensor.