The invention relates to a method for producing a flow sensor (1) based on a thin film, having a first heater and temperature measuring element (10) and at least one second heater and temperature measuring element (11). The heater and temperature measuring elements (10, 11) are spatially separated from each other, and a support structure (21) is provided which is designed to receive the heater and temperature measuring elements (10, 11). According to the invention, the production method has at least the following steps: providing a substrate (100); depositing a first photoresist (12) onto the substrate (100); depositing a second photoresist (13) onto the first photoresist (12); opening the first (12) and second photoresist (13) in order to produce a connection metallization; depositing a metal (14) in order to form the heater and temperature measuring elements (10, 11); structuring the deposited metal (14); and depositing a third photoresist (15) and removing the first photoresist (12) by means of at least on
