A culture device supplying an accurate amount of liquid into a culture bag has a culture bag having ports, a first bag holding portion having supporting surfaces supporting the culture bag, a rotation mechanism rotating the first bag holding portion, a liquid supplying mechanism supplying a liquid through a tube communicating with the ports a weight detector detecting the weight of the culture bag and the first bag holding portion, and a control portion, in which the control portion sets a first reference value according to a first detection information output from the weight detector in a first state and carries out a liquid supplying step of stopping the liquid supplying mechanism under the condition where a second detection information output from the weight detector when a liquid is supplied to the culturing bag reaches a first target value obtained by adding the weight of the liquid to be supplied to the first reference value.