In this laser beam machine 1, while a pressing portion 9 of an optical guide member 6 presses a lid 13 against a body 12 of a container, the optical guide member 6 annularly guides a laser beam propagated through an optical fiber 4 and outputs it from the pressing portion 9. Thereby, an annular processing region of the body 12 and the lid 13 is entirely irradiated with the laser beam at one time and the lid 13 can be joined to the body 12, whereby improving the working efficiency. Such improvement in working efficiency shortens the processing time and improves the production yield. Furthermore, this laser beam machine 1 does not need to be separately provided with a rotating mechanism for laser beam scanning and a pressurizing mechanism for the body 12 and the lid 13, so that construction of the machine can be significantly simplified.