A packaging container (1) includes a housing part (21) that houses a content, a flange part (22) provided on an outer circumference of an opening of the housing part (21) integrally with the housing part (21), a sealing ridge (23) provided on a top face of the flange part (22), annularly formed over an entire circumference of the flange part (22) so as to be protruded upward, and having a first protrusion (23a) that protrudes outward in a plane direction of the flange part (22) at a position corresponding to an opening start part, and a second protrusion (24) provided on the top face of the flange part (22) so as to be protruded upward, and forming a gap along an inner face of the first protrusion (23a) on an inner circumferential side of the first protrusion (23a) of the sealing ridge (23).