PROBLEM TO BE SOLVED: To provide a trocar including a space-saving camera development mechanism.SOLUTION: A trocar 1 includes a pipe part 2 for inserting a medical instrument into a body, and a head part 3. The pipe part 2 includes a pipe-part outer cylinder 21 and a pipe-part inner cylinder 22, and the pipe-part outer cylinder 21 is composed of a metal tube. The head part 3 includes a head-part outer cylinder 31 and a head-part inner cylinder 32, and the head-part outer cylinder 31 is composed of a resin. A thick-wall area 200 in which the resin covers over the rear end part of the metal tube and is integrally joined with the metal tube is formed at a rear end of the pipe-part outer cylinder 21. The head-part inner cylinder 32 is integrally molded or integrally joined with the pipe-part inner cylinder 22.SELECTED DRAWING: Figure 2
