To provide an engine capable of securing dynamic circularity of cylinder bore formed in a cylinder block by inhibiting chevron shape deformation of the cylinder head at low cost.

In the engine 10 provided with the cylinder head 20 having a combustion chamber 21 formed therein, the cylinder block 30 having cylinders formed therein in series, and head bolts 28 fixing the cylinder head 20 on the cylinder block 30, a first head bolt 28a and a fifth head bolt 28e fastened on both end parts of the cylinder block 30 out of the head bolts 28 are formed out of material having larger coefficient of linear expansion as compared to a second head bolt 28a, a third head bolt 28c and a fourth head bolt 28d fastened on other positions.