A cell culture apparatus is provided in which a plurality of culture vessels can be mounted and removed in a set, which has a regulation mechanism that can fix each culture vessel in the correct position, and which enables suppression of production costs. The cell culture apparatus has one or a plurality of concave portions, and can arrange and accommodate one or a plurality of culture vessels in the concave portions. Spring-type fixing devices are provided in the depth direction and the width direction, respectively, in each concave portion. The two spring-type fixing devices press against side surfaces of the culture vessel to fix the culture vessel in the culture vessel set. At this time, by pressing against the culture vessel at two points, the position of the culture vessel at the time of fixing can be maintained with good accuracy.