A blow molding apparatus includes an injection molding station (12) that injection-molds preforms (1A) held by N (N is an integer equal to or larger than 2) rows of holding plates (30), a temperature control station (14) that performs a temperature control operation on the preforms (1A), a blow molding station (16) that blow-molds the preforms into containers, and a row pitch change section (130) that changes the row pitch of the N rows of holding plates so that P1