Patent ID: 7595188

Claim:
An observation apparatus comprising: a sample tray that holds a container adapted to house a cultured cell and a culture medium and covered with a lid; an observation unit that serves for observation of the cultured cell; a shifting unit that shifts the sample tray relative to a light axis of the observation unit along a plane that is orthogonal to the light axis of the observation unit; a tray holding unit that detachably holds the sample tray to the shifting unit with good reproducibility; wherein the tray holding unit includes a tray attaching unit to which the sample tray is attached, and the tray attaching unit includes (i) a tray receiving portion that receives the sample tray, and (ii) a protruding portion that protrudes upward from the tray receiving portion, wherein the protruding portion has at least two side faces, each including a male dovetail and a pressing face which extends in a vertical direction and which faces against the at least two side faces; and wherein the sample tray includes: a flat face that makes face-contact with the tray receiving portion; and a depressed portion that is engaged with the protruding portion, the depressed portion including (i) a female dovetail that contacts one of the male dovetails of the protruding portion, (ii) a contact member that contacts the other male dovetail of the protruding portion, and (iii) a pressing unit that presses the pressing face of the protruding portion; and a container holding unit that holds the container by utilizing an elastic force, and at least one of the lid and one portion of the lid is made detachable, with the container being held in the sample tray by the container holding unit.