A ventilation member (10, 10A, 10B, 10C, 10D) attachable to a housing having an opening portion (22, 24) for ventilation, the ventilation member comprising: a cylindrical support body having a through hole configured to serve as an air passage between an interior space and an exterior space of the housing; an air-permeable membrane closing the through hole; a cover body (6, 19) provided at a position facing the air-permeable membrane so as to protect the air-permeable membrane; and a column portion provided between the cover body and the support body, the column portion being formed integrally with both the cover body (6, 19) and the support body so as to fix the cover body (6, 19) to the support body, wherein the through hole includes (a) a first portion having a relatively large inner diameter and (b) a second portion having a relatively small inner diameter, an annular ridge portion is formed on an outer peripheral surface of the support body along a circumferential direction of the support body, and (i) when the housing has, as the opening portion, a nozzle opening portion projecting from a surface of the housing, the ventilation member (10, 10A, 10B, 10C, 10D) can be attached to the housing by fitting the support body onto the nozzle opening portion so that an inner peripheral surface of the support body in the first portion is in close contact with an outer peripheral surface of the nozzle opening portion, and (ii) when the housing has, as the opening portion, a recess opening portion recessed from the surface of the housing, the ventilation member (10, 10A, 10B, 10C, 10D) can be attached to the housing by fitting the support body into the recess opening portion so that the ridge portion is in close contact with an inner peripheral surface of the recess opening portion, characterized in that the column portion is located on an annular open end face of the second portion of the through hole, and in a plane view of an opening of the second portion, the column portion has a bridge shape extending from a first position on the open end face of the second portion to a second position on the open end face of the second portion so that the opening of the second portion is divided into two or more sections by the column portion. a cylindrical support body having a through hole configured to serve as an air passage between an interior space and an exterior space of the housing; an air-permeable membrane closing the through hole; a cover body (6, 19) provided at a position facing the air-permeable membrane so as to protect the air-permeable membrane; and a column portion provided between the cover body and the support body, the column portion being formed integrally with both the cover body (6, 19) and the support body so as to fix the cover body (6, 19) to the support body, wherein the through hole includes (a) a first portion having a relatively large inner diameter and (b) a second portion having a relatively small inner diameter, an annular ridge portion is formed on an outer peripheral surface of the support body along a circumferential direction of the support body, and (i) when the housing has, as the opening portion, a nozzle opening portion projecting from a surface of the housing, the ventilation member (10, 10A, 10B, 10C, 10D) can be attached to the housing by fitting the support body onto the nozzle opening portion so that an inner peripheral surface of the support body in the first portion is in close contact with an outer peripheral surface of the nozzle opening portion, and (ii) when the housing has, as the opening portion, a recess opening portion recessed from the surface of the housing, the ventilation member (10, 10A, 10B, 10C, 10D) can be attached to the housing by fitting the support body into the recess opening portion so that the ridge portion is in close contact with an inner peripheral surface of the recess opening portion, (i) when the housing has, as the opening portion, a nozzle opening portion projecting from a surface of the housing, the ventilation member (10, 10A, 10B, 10C, 10D) can be attached to the housing by fitting the support body onto the nozzle opening portion so that an inner peripheral surface of the support body in the first portion is in close contact with an outer peripheral surface of the nozzle opening portion, and (ii) when the housing has, as the opening portion, a recess opening portion recessed from the surface of the housing, the ventilation member (10, 10A, 10B, 10C, 10D) can be attached to the housing by fitting the support body into the recess opening portion so that the ridge portion is in close contact with an inner peripheral surface of the recess opening portion, characterized in that the column portion is located on an annular open end face of the second portion of the through hole, and in a plane view of an opening of the second portion, the column portion has a bridge shape extending from a first position on the open end face of the second portion to a second position on the open end face of the second portion so that the opening of the second portion is divided into two or more sections by the column portion.