To provide an engine sealing structure for stably obtaining and maintaining appropriate surface pressure between both structures constructing an engine on a seal surface.

A cylinder block 2 of an engine is constructed of a cylinder block body 3 and a cylinder block exterior wall 4 in separate bodies and their joining surfaces are sealed with a seal member 31. The cylinder block exterior wall 4 is formed of resin material and the seal member 31 is formed of soft elastic material. The seal member 31 is buried in a circular shape in a surface of the cylinder block exterior wall 4 to be sealed and in a body so that its tip portion can be resiliently deformed.