A culture apparatus comprising: an inner box configured to form a culture chamber; an outer box configured to cover the inner box; a fan configured to circulate gas inside the culture chamber through an air passage provided in the inner box within the culture chamber; a first through hole configured to penetrate a wall configuring a part of the air passage in the inner box; a second through hole configured to penetrate the wall and disposed at a position at which a flow velocity of the gas circulated through the air passage by the fan is lower than a flow velocity of the gas around the first through hole; a connecting pipe configured to connect the first through hole and the second through hole outside of the inner box; and a sensor configured to detect a concentration of the gas flowing in the culture chamber.