Pressure control valve, in particular for adjusting negative pressure in a crankcase of an internal combustion engine, - with a valve housing, which comprises a first opening and a second opening, - with a valve member, which is arranged to be stroke-adjustable in the valve housing for controlling the throughflow cross-section of a gas pathway connecting the first opening to the second opening, - wherein the valve member comprises a support body with a first membrane and a second membrane, - wherein the first membrane in the valve housing separates in a gas-tight manner a first chamber, which communicates with the first opening and the second opening, from a second chamber, which communicates with a third opening of the valve housing, - wherein the second membrane in the valve housing separates in a gas-tight manner the second chamber from a third chamber, which communicates through the valve member with the first chamber, - wherein the first membrane and the second membrane are formed to be integral with a one-piece membrane body moulded onto the support body, - wherein the valve body comprises a control contour, which, as a function of its distance from an edging of the first opening facing the valve body, controls the throughflow cross-section of the gas pathway, - wherein the control contour is formed to be integral with the membrane body, - wherein the control contour is formed on a control section of the membrane body, - wherein at least one opening compression spring (23, 23') is provided which is supported on the valve housing and on the support body of the valve member, characterised in that - the control section of the membrane body is arranged on a side of the support body facing the first chamber, - the support body comprises openings which are penetrated by the moulded membrane body such that the membrane body comprises the membranes (10, 11) on one side of the support body and comprises the control section on the other side of the support body, - the support body comprises an annular inner collar and an annular outer collar which extend coaxially relative to one another and coaxially to the control section on the side of the support body facing the first chamber, - the control section is arranged radially between the inner collar and the outer collar, - the respective opening compression spring (23, 23') is supported radially between the control section and the inner collar or radially between the control section and the outer collar on the support body. - with a valve housing, which comprises a first opening and a second opening, - with a valve member, which is arranged to be stroke-adjustable in the valve housing for controlling the throughflow cross-section of a gas pathway connecting the first opening to the second opening, - wherein the valve member comprises a support body with a first membrane and a second membrane, - wherein the first membrane in the valve housing separates in a gas-tight manner a first chamber, which communicates with the first opening and the second opening, from a second chamber, which communicates with a third opening of the valve housing, - wherein the second membrane in the valve housing separates in a gas-tight manner the second chamber from a third chamber, which communicates through the valve member with the first chamber, - wherein the first membrane and the second membrane are formed to be integral with a one-piece membrane body moulded onto the support body, - wherein the valve body comprises a control contour, which, as a function of its distance from an edging of the first opening facing the valve body, controls the throughflow cross-section of the gas pathway, - wherein the control contour is formed to be integral with the membrane body, - wherein the control contour is formed on a control section of the membrane body, - wherein at least one opening compression spring (23, 23') is provided which is supported on the valve housing and on the support body of the valve member, characterised in that - the control section of the membrane body is arranged on a side of the support body facing the first chamber, - the support body comprises openings which are penetrated by the moulded membrane body such that the membrane body comprises the membranes (10, 11) on one side of the support body and comprises the control section on the other side of the support body, - the support body comprises an annular inner collar and an annular outer collar which extend coaxially relative to one another and coaxially to the control section on the side of the support body facing the first chamber, - the control section is arranged radially between the inner collar and the outer collar, - the respective opening compression spring (23, 23') is supported radially between the control section and the inner collar or radially between the control section and the outer collar on the support body.