Cooling structure of internal combustion engine

A cooling structure of an internal combustion engine, the cooling structure comprising:

• a cylinder head:
• and
• a coolant temperature sensor including a temperature sensing portion, wherein
• the cylinder head has a cylinder block attachment surface and a cylinder head cover attachment surface,
• the cylinder head includes an exhaust manifold,
• the cylinder head has a first water jacket through which a coolant for cooling a combustion chamber flows and a second water jacket through which a coolant for cooling the exhaust manifold flows, the first water jacket and the second water jacket are defined within the cylinder head,
• the cylinder head includes a joining portion in which the coolant discharged from, the first water jacket and the coolant discharged from the second water jacket join together,
• the joining portion has a first coolant passage,
• a second coolant passage is disposed at a position downstream of the joining portion,
• the temperature sensing portion is disposed in the second coolant passage,
• a coolant outlet of the second water jacket is defined in the first coolant passage, and the coolant outlet of the second water jacket is located at a position on the cylinder head cover attachment surface side in the first coolant passage, and
• the temperature sensing portion is located at a position on the cylinder block attachment surface side in the second coolant passage.