A cooler using a cooling medium, the cooler comprising: a shell which is a flat, sealed container and configured to allow the cooling medium to flow therein; an inflow side pipe which is formed to project from the shell and is configured to introduce the cooling medium into the shell; an outflow side pipe which is formed to project from the shell and is configured to discharge the cooling medium from the shell; and a bottom plate which is fixed on a bottom surface of the shell, wherein the bottom plate comprises: a plurality of protruded portions (23, 25), a part of which protrudes from the shell along a direction of projection of the inflow side pipe and the outflow side pipe, and each of which is fixed on each pipe; and a plurality of fixed portions (24, 26), used for fixing the shell to a structure to be cooled and in which a portion adjacent to each protruded portion (23,25) protrudes from the shell and a through hole to which a fastening member is inserted is formed in the fixed portion, and wherein a notched portion (40, 42) which is formed between the fixed portion (24, 26), and the protruded portion (23, 25) by being cut along a direction of projection of each pipe and which allows deformation of the protruded portion (23, 25) upon reception of an impactive force along an axial direction of each pipe is formed on the bottom plate. a shell which is a flat, sealed container and configured to allow the cooling medium to flow therein; an inflow side pipe which is formed to project from the shell and is configured to introduce the cooling medium into the shell; an outflow side pipe which is formed to project from the shell and is configured to discharge the cooling medium from the shell; and a bottom plate which is fixed on a bottom surface of the shell, wherein the bottom plate comprises: a plurality of protruded portions (23, 25), a part of which protrudes from the shell along a direction of projection of the inflow side pipe and the outflow side pipe, and each of which is fixed on each pipe; and a plurality of fixed portions (24, 26), used for fixing the shell to a structure to be cooled and in which a portion adjacent to each protruded portion (23,25) protrudes from the shell and a through hole to which a fastening member is inserted is formed in the fixed portion, and wherein a notched portion (40, 42) which is formed between the fixed portion (24, 26), and the protruded portion (23, 25) by being cut along a direction of projection of each pipe and which allows deformation of the protruded portion (23, 25) upon reception of an impactive force along an axial direction of each pipe is formed on the bottom plate. a plurality of protruded portions (23, 25), a part of which protrudes from the shell along a direction of projection of the inflow side pipe and the outflow side pipe, and each of which is fixed on each pipe; and a plurality of fixed portions (24, 26), used for fixing the shell to a structure to be cooled and in which a portion adjacent to each protruded portion (23,25) protrudes from the shell and a through hole to which a fastening member is inserted is formed in the fixed portion, and wherein a notched portion (40, 42) which is formed between the fixed portion (24, 26), and the protruded portion (23, 25) by being cut along a direction of projection of each pipe and which allows deformation of the protruded portion (23, 25) upon reception of an impactive force along an axial direction of each pipe is formed on the bottom plate.