A method for determining the propagation times of an ultrasonic pulse, comprising the steps of: (a) selecting a base wavelet; (b) sending an ultrasonic measuring pulse, (c) passing through a measuring section, (d) receiving and sampling the emitted ultrasonic measuring pulse as a received signal, (e) scaling the received signal to an accuracy Δt for the signal propagation time to be determined, comprising: inserting at least one zero between each two sampling points of the ultrasonic measuring pulse such that the inserting of k zeroes at k ∈ N corresponds to a temporal accuracy of Δt = 1 fS k + 1, wherein f S is the sampling rate of the received signal, (f) performing a wavelet transformation on the basis of the selected base wavelet and the scaled received signal, and (g) determining the propagation time of the ultrasonic measuring pulse from the result of the wavelet transformation, wherein the result of the wavelet transformation is a function W(a, b), wherein the first parameter a of the wavelet transformation is a real nonzero number, and the second parameter b of the wavelet transformation is a natural number, and wherein the step of determining the propagation time comprises: determining the optimum value of the first parameter a opt of the wavelet, comprising the steps of determining the maximum W max (a) from W(a, b) separately to each value of the first parameter a and for any values of the second parameter b, and of determining the optimum value of the first parameter a opt from the position of the maximum of W max (a); selecting the wavelet transformation with the optimum value of the first parameter W(a opt, b), determining the second parameter b, at the location of which the pulse belonging to the ultrasonic measuring pulse lies in the received signal, and determining the propagation time of the ultrasonic measuring pulse from the product of the determined second parameter b and the temporal accuracy Δt. (a) selecting a base wavelet; (b) sending an ultrasonic measuring pulse, (c) passing through a measuring section, (d) receiving and sampling the emitted ultrasonic measuring pulse as a received signal, (e) scaling the received signal to an accuracy Δt for the signal propagation time to be determined, comprising: inserting at least one zero between each two sampling points of the ultrasonic measuring pulse such that the inserting of k zeroes at k ∈ N corresponds to a temporal accuracy of Δt = 1 fS k + 1, wherein f S is the sampling rate of the received signal, (f) performing a wavelet transformation on the basis of the selected base wavelet and the scaled received signal, and (g) determining the propagation time of the ultrasonic measuring pulse from the result of the wavelet transformation, determining the optimum value of the first parameter a opt of the wavelet, comprising the steps of determining the maximum W max (a) from W(a, b) separately to each value of the first parameter a and for any values of the second parameter b, and of determining the optimum value of the first parameter a opt from the position of the maximum of W max (a); selecting the wavelet transformation with the optimum value of the first parameter W(a opt, b), determining the second parameter b, at the location of which the pulse belonging to the ultrasonic measuring pulse lies in the received signal, and determining the propagation time of the ultrasonic measuring pulse from the product of the determined second parameter b and the temporal accuracy Δt.