The present invention relates to a pump for delivering under pressure various liquids including water. The temperature of the handled liquid in a pump casing (1) is detected by a thermistor (51). If an increase in the temperature per time of the handled liquid is greater than a predetermined value, then the pump is shut down, or the flow rate or pressure of the liquid is changed depending on the temperature of the handled liquid detected by the thermistor based on a predetermined control program. <IMAGE>
