In this invention, a grommet structure in an incubator includes a grommet attaching portion provided to the enclosure of the incubator and a grommet member attached to the grommet attaching portion. The grommet member includes a longitudinal member holding incision to hold a longitudinal member such as an oxygen supply tube that extends through it. The longitudinal member holding incision forms at least one substantially S-shaped shape (in other words, a substantially sine-curved shape) and/or a substantially waving shape. This invention can provide the grommet structure in the incubator, in which the longitudinal member such as an oxygen supply tube held by the longitudinal incision of the grommet member and extending through the incision is less likely to move accidentally in the longitudinal direction of the incision or in the longitudinal direction of the longitudinal member. Also, a gap through which the inside and outside of the enclosure communicate with each other can be small even when the longitudinal member extends through the incision.
