to the above preferred embodiment of the present invention there is shown in fig5 charging effects of the intake system of the present invention and a conventional intake system under full throttle conditions the conventional intake system used for comparison is provided with two intake pipes independently connected to primary and secondary intake ports of each rotary cylinder respectively both intake systems were cooperated with a 645 cc two rotor rotary piston engine having a compression ratio e of 9 4 and is not provided with any turbo charger as apparent from fig5 charging efficiency is considerably improved in the intake system compared to the conventional one fig6 shows an intake system in accordance with another preferred embodiment of the present invention which cooperates with a vertical type four cylinder reciprocating piston engine which is hereinafter referred to as a v 4 engine ve4 as shown the v 4 engine ve has four namely first to fourth cylinders 30a 30b 30c and 30d each being provided with primary secondary and first and second auxiliary intake ports 3a 4a and 5a the intake system is has a main intake pipe 10 provided with an air cleaner 11 an air flow meter 12 a primary throttle valve 13 and a surge tank 14 arranged in order from the upstream side thereof the main intake pipe 10 branches off into four first common intake pipes 15 from the surge tank 14 each first common intake pipe 15 branches off into two namely primary and secondary intake pipes 15a and 15b near each cylinder 30a 30d which are respectively connected to the primary and secondary intake ports 2a and 3a of each cylinder 30a 30d the secondary intake pipe 15b is provided with a secondary throttle.