Internal combustion engine, and integrated cam bracket of internal combustion engine

An internal combustion engine, includes: a cylinder head (12) including; a bearing holder (34); and an integrated cam bracket (14) held to the cylinder head (12), in a manner that a first cam shaft and a second cam shaft in parallel with each other in a direction of a line of a cylinder are sandwiched between the cylinder head (12) and the integrated cam bracket (14). The integrated cam bracket (14) includes; a first side frame (18F) and a second side frame (18S), bearing beams ä36(#1), 36(#2), 36(#3), 36(#4)ü bridging across the first side frame (18F) and the second side frame (18S), the first cam shaft and the second cam shaft being rotatably born by the bearing beams ä36(#1), 36(#2), 36(#3), 36(#4)ü with the bearing holder (34), a center beam (38) disposed between the first side frame (18F) and the second side frame (18S) and extending in parallel with the first side frame (18F) and the second side frame (18S), and a void portion (40: 40F, 40S) collinear with the center beam (38) and free from the center beam (38).