A prismatic battery having advantages of both a rectangular battery and a cylindrical battery and having excellent properties is provided. Furthermore, a method of manufacturing the prismatic battery, suppressing the occurrence of defects in manufacturing the prismatic batteries and having an excellent productivity is provided. A prismatic battery including: an electrode plate group, an electrolyte and a battery case for accommodating the electrode plate group and the electrolyte; wherein the side face of the battery case includes a cylindrical head portion; a prismatic body potion for accommodating the electrode plate group and the electrolyte; and a transition portion located between the body portion and the head portion.