Jiri,
Each transistor is a common collector amplifier. The input is on the base and the output is on the emitter, therefore the collector is "common" to both.
This common collector (emitter output) setup gives a low output impedance and the base currents are used by the load (not wasted). No phase splitter is needed.
As drawn, crossover distortion is a potential problem. The output is also not rail to rail. This circuit is used for old designs like LM324.
However, almost all modern design have common emitter (collector outputs) that will give rail to rail output performance.
Many times the bi-polar transistors are replaced with MOSFETs.