The invention relates to a device for monitoring the observance of a treatment involving administration of gas to an individual, comprising a gas inlet (2) and a gas outlet (3), a gas passage (1) fluidically connecting the gas inlet (2) to the gas outlet (3), at least one pressure sensor, and a flow-rate determining device (4, 5, 6, 7), arranged in the gas passage (1), for determining the flow rate of the gas flowing through said gas passage (1). The flow-rate determining device (4, 5, 6, 7) comprises at least one heat-sensitive cell (4).
