A capacitor comprising: a capacitor element being formed by overlaying and winding an anode foil and a cathode foil with a separator interposed between the anode foil and the cathode foil and by being impregnated with an electrolytic solution; an exterior case for housing the capacitor element, the exterior case having a cylindrical shape with a bottom; and an opening sealing body for sealing an opening of the exterior case, a recessed part being formed on an inner bottom of the exterior case, the recessed part having: a first inclined surface radially expanding from a central part area of the inner bottom, the central part area of the inner bottom being the deepest portion of the inner bottom; and a second inclined surface continuing to an outer edge of the first inclined surface, the second inclined surface being steeper than the first inclined surface, a weak portion being formed inside of the recessed part, a groove part being formed outside of the inner bottom of the exterior case, a thick-wall portion being formed on a periphery of the recessed part, and an outer edge portion of a surface of the capacitor element being in contact with the thick-wall portion, the surface facing the inner bottom of the exterior case; wherein the diameter of the capacitor element is larger than the diameter of the recessed part. a capacitor element being formed by overlaying and winding an anode foil and a cathode foil with a separator interposed between the anode foil and the cathode foil and by being impregnated with an electrolytic solution; an exterior case for housing the capacitor element, the exterior case having a cylindrical shape with a bottom; and an opening sealing body for sealing an opening of the exterior case, a recessed part being formed on an inner bottom of the exterior case, the recessed part having: a first inclined surface radially expanding from a central part area of the inner bottom, the central part area of the inner bottom being the deepest portion of the inner bottom; and a second inclined surface continuing to an outer edge of the first inclined surface, the second inclined surface being steeper than the first inclined surface, a weak portion being formed inside of the recessed part, a groove part being formed outside of the inner bottom of the exterior case, a thick-wall portion being formed on a periphery of the recessed part, and an outer edge portion of a surface of the capacitor element being in contact with the thick-wall portion, the surface facing the inner bottom of the exterior case; wherein the diameter of the capacitor element is larger than the diameter of the recessed part. a first inclined surface radially expanding from a central part area of the inner bottom, the central part area of the inner bottom being the deepest portion of the inner bottom; and a second inclined surface continuing to an outer edge of the first inclined surface, the second inclined surface being steeper than the first inclined surface, a weak portion being formed inside of the recessed part, a groove part being formed outside of the inner bottom of the exterior case, a thick-wall portion being formed on a periphery of the recessed part, and an outer edge portion of a surface of the capacitor element being in contact with the thick-wall portion, the surface facing the inner bottom of the exterior case; wherein the diameter of the capacitor element is larger than the diameter of the recessed part.