Sample observation system and sample observation process

A sample observation process of a sample whose vertical direction is defined by gravity, the process comprising:

• retaining a liquid containing the sample in a sample holder having at least one penetrating hole;
• and
• observing the sample in a condition in which an observation unit for observing the sample and the direction of the gravity which acts on the sample have an arbitrary angle therebetween further in a condition in which the sample holder and the observation unit have a fixed relative angle therebetween.

A process for observing a plurality of samples simultaneously, comprising:

• disposing a plurality of biological samples respectively in positions on a plane which positions correspond to focal fields of an image acquisition unit;
• and
• rotating both the image acquisition unit and the plane around an axis on the plane while keeping the positional relationship of the image acquisition unit and the plane.