To simplify the structure of the penetrating part of a piping parts by arranging an outer bracket between a tube main body for connecting an outer casing and an inner casing to each other and the outer casing, and also interposing an intermediate seal means between the outer bracket and the tube main body.

In a tube main body 20 in the oiling line 10 of a gas turbine engine, an outer casing A and an inner casing B are connected to each other in a penetrating condition, an outer bracket 13 is arranged between the outer casing A and the tube main body 20. An intermediate seal means 30 is interposed between the outer bracket 13 and the tube main body 20, and provided with an adapter 32 and a tube seal 31. A seal function is applied between the inner casing B and the tube main body 20, an inner installing means 40 is interposed between the inner casing B and the tube main body 20, and it comprises an inner bracket 41 and a housing 42 interposed between the inner bracket 41 and the tube main body 20 and connected to an inner piping P.