A blow-by gas device of a supercharger-equipped engine includes a blow-by gas passage that introduces blow-by gas into an intake passage via a positive crankcase ventilation (PCV) valve. A supercharger has a supercharger rotor provided integrally with a rotation shaft rotatably supported on a bearing part. A space communicating with the bearing part is connected to a communication passage. The communication passage guides the blow-by gas into the space.