A removable pressure sensor (30, 30a) which is configured to be removably mounted in an intermediate part of an elastically deformable tube for transferring a liquid, the removable pressure sensor (30, 30a) comprising: a main body portion; and a pressure measurement element that is disposed in the main body portion, wherein the main body portion comprises a base portion having a tube mounting recessed portion into which the intermediate part of the tube is removably fitted so as to cause the tube to be elastically deformed and to cause a circuit pressure of the liquid inside the tube to be measured by the pressure measurement element, and a lid portion configured to hold the tube inside the tube mounting recessed portion in a state in which the tube mounting recessed portion of the base portion is closed, wherein a width of a cross section of the tube mounting recessed portion is configured to be smaller than an external dimension of the tube, characterized in that the removable pressure sensor (30, 30a) further comprises: a temperature sensor that measures a temperature of an environment in which the tube is positioned; and a control unit that acquires temperature information of the environment from the temperature sensor, acquires the circuit pressure of the liquid inside the tube from the pressure measurement element, and corrects the circuit pressure of the liquid inside the tube measured by the pressure measurement element, in accordance with a value of the temperature. a main body portion; and a pressure measurement element that is disposed in the main body portion, wherein the main body portion comprises a base portion having a tube mounting recessed portion into which the intermediate part of the tube is removably fitted so as to cause the tube to be elastically deformed and to cause a circuit pressure of the liquid inside the tube to be measured by the pressure measurement element, and a lid portion configured to hold the tube inside the tube mounting recessed portion in a state in which the tube mounting recessed portion of the base portion is closed, wherein a width of a cross section of the tube mounting recessed portion is configured to be smaller than an external dimension of the tube, characterized in that the removable pressure sensor (30, 30a) further comprises: a temperature sensor that measures a temperature of an environment in which the tube is positioned; and a control unit that acquires temperature information of the environment from the temperature sensor, acquires the circuit pressure of the liquid inside the tube from the pressure measurement element, and corrects the circuit pressure of the liquid inside the tube measured by the pressure measurement element, in accordance with a value of the temperature. a temperature sensor that measures a temperature of an environment in which the tube is positioned; and a control unit that acquires temperature information of the environment from the temperature sensor, acquires the circuit pressure of the liquid inside the tube from the pressure measurement element, and corrects the circuit pressure of the liquid inside the tube measured by the pressure measurement element, in accordance with a value of the temperature.