A blow molding apparatus comprising: N rows of holding plates, N being an integer equal to or larger than 2, wherein each of the N rows of holding plates to be transferred along a transfer direction holding a plurality of neck molds; a support-transfer member (20A to 20D) that transfers the N rows of holding plates, the support-transfer member (20A to 20D) supporting the N rows of holding plates so that a row pitch of the N rows of holding plates can be changed; an injection molding station that injection-molds a plurality of preforms, the injection molding station including N rows of injection cavity molds that are clamped to the plurality of neck molds that are held by each of the N rows of holding plates; a temperature control station that includes N rows of temperature-controlled pot molds that are disposed on a downstream side of the injection molding station in the transfer direction, and performs a temperature control operation by disposing the plurality of preforms held by the N rows of holding plates in the N rows of temperature-controlled pot molds; a blow molding station that includes N rows of blow molds (60, 64) that are disposed on a downstream side of the temperature control station in the transfer direction, and blow-molds the plurality of preforms held by the N rows of holding plates into a plurality of containers; and a row pitch change section that is adapted to change the row pitch of the N rows of holding plates, wherein P1 is the row pitch of the N rows of holding plates when they hold the plurality of preforms that have been injection-molded and P2 is the row pitch of the N rows of holding plates when they hold the plurality of containers that have been blow-molded, characterized in that P3 is the row pitch of the N rows of holding plates when they hold the plurality of preforms that are transferred to the N rows of blow molds (60, 64) that are opened and the row pitch change section is adapted to change the row pitch of the N rows of holding plates so that P1<P3<P2 is satisfied. N rows of holding plates, N being an integer equal to or larger than 2, wherein each of the N rows of holding plates to be transferred along a transfer direction holding a plurality of neck molds; a support-transfer member (20A to 20D) that transfers the N rows of holding plates, the support-transfer member (20A to 20D) supporting the N rows of holding plates so that a row pitch of the N rows of holding plates can be changed; an injection molding station that injection-molds a plurality of preforms, the injection molding station including N rows of injection cavity molds that are clamped to the plurality of neck molds that are held by each of the N rows of holding plates; a temperature control station that includes N rows of temperature-controlled pot molds that are disposed on a downstream side of the injection molding station in the transfer direction, and performs a temperature control operation by disposing the plurality of preforms held by the N rows of holding plates in the N rows of temperature-controlled pot molds; a blow molding station that includes N rows of blow molds (60, 64) that are disposed on a downstream side of the temperature control station in the transfer direction, and blow-molds the plurality of preforms held by the N rows of holding plates into a plurality of containers; and a row pitch change section that is adapted to change the row pitch of the N rows of holding plates, wherein P1 is the row pitch of the N rows of holding plates when they hold the plurality of preforms that have been injection-molded and P2 is the row pitch of the N rows of holding plates when they hold the plurality of containers that have been blow-molded, characterized in that P3 is the row pitch of the N rows of holding plates when they hold the plurality of preforms that are transferred to the N rows of blow molds (60, 64) that are opened and the row pitch change section is adapted to change the row pitch of the N rows of holding plates so that P1<P3<P2 is satisfied.