An isolator comprising: a manipulation chamber isolated from the external atmosphere; the front side of the manipulation chamber being provided with gloves into which an operator's hands can be inserted to manipulate objects inside the manipulation chamber; a door (22L, 22R) for opening and closing a portal formed on the manipulation chamber; the portal being formed on a side wall with respect to the front side; characterized by a linear guide mechanism for guiding a linear motion of the front-side edge of the door (22L, 22R) along the portal; and a rotation guide mechanism (40U, 40D) defining a rotation of the door (22L, 22R) about an axis coinciding with the front-side edge, wherein the rotation guide mechanism comprises a lever member (40U, 40D) in which a base end is rotatably supported by an inner surface of the manipulation chamber and a tip end is rotatably connected to the door (22L, 22R); wherein the door (22L, 22R) is closed by positioning the front-side edge at the front side of the manipulation chamber, and the door (22L, 22R) is opened inward into the manipulation chamber by moving the front-side edge toward the back side, which faces the front side of the manipulation chamber, while rotating the door (22L, 22R) about the front-side edge; and on the surface of the door (22L, 22R) facing the manipulation chamber, an operating element for operating the door (22L, 22R) is provided, wherein the operating element is positioned within the operational range of the gloves at about the same level as the gloves or slightly lower and the position of the operating element is operable by an operator inserting one's hands into the gloves. a manipulation chamber isolated from the external atmosphere; the front side of the manipulation chamber being provided with gloves into which an operator's hands can be inserted to manipulate objects inside the manipulation chamber; a door (22L, 22R) for opening and closing a portal formed on the manipulation chamber; the portal being formed on a side wall with respect to the front side; characterized by a linear guide mechanism for guiding a linear motion of the front-side edge of the door (22L, 22R) along the portal; and a rotation guide mechanism (40U, 40D) defining a rotation of the door (22L, 22R) about an axis coinciding with the front-side edge, wherein the rotation guide mechanism comprises a lever member (40U, 40D) in which a base end is rotatably supported by an inner surface of the manipulation chamber and a tip end is rotatably connected to the door (22L, 22R); wherein the door (22L, 22R) is closed by positioning the front-side edge at the front side of the manipulation chamber, and the door (22L, 22R) is opened inward into the manipulation chamber by moving the front-side edge toward the back side, which faces the front side of the manipulation chamber, while rotating the door (22L, 22R) about the front-side edge; and on the surface of the door (22L, 22R) facing the manipulation chamber, an operating element for operating the door (22L, 22R) is provided, wherein the operating element is positioned within the operational range of the gloves at about the same level as the gloves or slightly lower and the position of the operating element is operable by an operator inserting one's hands into the gloves.