To provide a Petri dish having a structural feature applicable to various biological environments or sample sizes appropriate to required specific uses.

The Petri dish 1 capable of being used even if turned upside down has the structural feature allowing a selection to be made for different uses concerning acceptance, growth and examination of a biological substrate. The Petri dish 1 can be turned upside down for selecting a side of the dish having a desired structural feature. The dish capable of being used even if turned upside down has the one side applied to a use requiring the entire surface area of the bottom of the dish and the other side applied to a use requiring a deeper volume over a smaller surface area.