Process for making sensor for detecting fluid flow velocity or flow amount

In a process for making a sensor for detecting a fluid flow velocity or flow amount, which comprises a step of applying an electroconductive paste containing platinum powder to the outer surface of an insulating tube, and firing the paste, thereby forming a platinum film on the outer surface of the insulating tube, a step of preparing a spiral groove on the platinum film by laser processing, thereby forming a platinum resistor band having a predetermined resistance while eliminating platinum remains from the groove, and a step of coating the platinum resistor band with amorphous glass, the improvement comprising said electroconductive paste containing platinum powder consisting of 65-85% by weight of platinum powder and 35-15% by weight of an organic vehicle, with said platinum powder uniformly dispersed in said organic vehicle, and the firing of the paste is carried out at a temperature of 1100.degree. to 1400.degree. C. for at least 20 minutes, whereby a sensor for detecting a fluid flow velocity or flow amount with a high precision of resistance and a high mechanical strength at low cost is formed.