To provide an engine capable of improving atomization efficiency in fuel.

This engine 120 has a cylinder block 122, a cylinder head 121 forming an intake port 131 for introducing air to a combustion chamber C via an intake valve opening 128, a fuel injection device 170 having an injection port 171 injecting the fuel toward the intake valve opening 128, a chamber 174 for positioning the injection port 171 inside, a sub-passage 180 communicating with a throttle body 160 and the chamber 174, an adapter 10 having a cylindrical wall part 11 for partitioning the chamber 174 into the inside-outside in the radial direction by extending in the injection direction (forward in the axial S1 direction) of the injection device 170 while surrounding the injection port 171 and forming a communicating port 15 in a vicinal part of the injection port 171 of the cylindrical wall part 11, and first and second sealing parts 31 and 32 for sealing a part between a wall surface 137a for constituting the chamber 174 and an outer surface of the adapter 10 in a position for longitudinally sandwiching the communicating port 15 in the axis S1 direction.