Engine cam shaft

The invention relates to an engine cam shaft which comprises a gas distribution cam shaft (1), an oil supplying cam shaft (2), an oil pump driving shaft (3), an oil injection pump (4), an outer rotor (5) and an inner rotor (6), wherein the oil supplying cam shaft (2) is installed in the middle of the gas distribution cam shaft (1), the oil pump driving shaft (3) is installed at one end of the gas distribution cam shaft (1), the outer rotor (5) is connected with the oil pump driving shaft (3), the outer rotor (5) is installed inside the inner rotor (6), and the oil injection pump (4) is in periodic contact connection with the oil supplying cam shaft (2). The oil pump driving shaft (3), the gas distribution cam shaft (1) and the oil supplying cam shaft (2) are installed in an integrated structure. The engine cam shaft is simple in structure and improves whole reliability of an engine.