To provide an internal combustion engine capable of using any kinds of fuels and generates rotational force by using blast produced by explosion of the fuel.

An internal combustion engine 100 includes an impeller unit 10, a combustion unit 20, a communicating path 30 and a valve 40. The impeller unit 10 comprises a rotation shaft member 12 having a rotation shaft 11 and a plurality of impeller members 13 outwardly extending from the rotation shaft member. The combustion unit 20 mixes a fuel with gas inside and ignites the mixture to explode. The communication path 30 communicates the combustion unit 20 with the impeller unit 10. The valve 40 is disposed inside a connecting portion between the combustion unit 20 and the communication path 30, and opens when the fuel explodes inside the combustion unit 20. When explosion occurs in the combustion unit 20, the valve 40 opens to transfer the blast generated by the explosion to the impeller members 13 of the impeller unit 10 through the communication path 30, which rotates the impeller unit 10.