To solve problems in a conventional knocking suppression method wherein reduction itself of combustion speed of air-fuel mixture at combustion later time for combustion initial time cannot be improved and knocking prevention effect is reduced in inverse proportion to increase in compression ratio and intake efficiency of intake of an internal combustion engine.

This knocking suppression device is provided with an ignition plug 25 in which an ignition gap 24 is arranged in a central part in the radial direction of a combustion chamber 14 of the internal combustion engine and a high pressure gas injection valve 17 arranged in an outer peripheral end part of the combustion chamber 14 so that it is positioned most apart from an exhaust port 17 opened in the combustion chamber 14 and having a nozzle 26 for injecting high pressure gas along an inner peripheral wall of a cylinder 12 surrounding the combustion chamber 14 immediately after ignition of the ignition plug 25. Turbulent flow by high pressure gas in the combustion chamber 14 is generated at combustion later time to control propagation of flame and avoid occurrence of knocking.