A scramjet engine comprising: a first passage forming member having a first surface; and a second passage forming member having a second surface opposing to the first surface, wherein a passage is formed between the first surface and the second surface to connect a front opening and a rear opening provided downstream of the front opening, wherein the passage comprises: an upstream zone configured to generate a flow of compressed air obtained by compressing an air taken in through the front opening; a combustion zone connected downstream of the upstream zone and configured to combust a mixture in which fuel is injected into the flow of compressed air, to generate a combustion gas; and a downstream zone connected downstream of the combustion zone and configured to exhaust the combustion gas toward the rear opening, wherein a cavity is provided on the first surface in the combustion zone, wherein the first passage forming member comprises: at least one convex section located in the upstream zone and provided on the first surface to protrude toward the second surface from the first surface; a first fuel injection section configured to inject fuel to the flow of compressed air; and a second fuel injection section configured to inject fuel to the cavity, and wherein the second passage forming member comprises a third fuel injection section configured to inject fuel to a direction toward the first surface from the second surface in the passage, characterized in that the first fuel injection section is configured to inject the fuel to the flow of compressed air through a first fuel nozzle provided for the convex section, and the third fuel injection section is configured to inject the fuel to a direction toward the first surface from the second surface in the passage through a second fuel nozzle provided on the second surface in the downstream zone such that the injected fuel restrains or stops the flow of the combustion gas. a first passage forming member having a first surface; and a second passage forming member having a second surface opposing to the first surface, wherein a passage is formed between the first surface and the second surface to connect a front opening and a rear opening provided downstream of the front opening, wherein the passage comprises: an upstream zone configured to generate a flow of compressed air obtained by compressing an air taken in through the front opening; a combustion zone connected downstream of the upstream zone and configured to combust a mixture in which fuel is injected into the flow of compressed air, to generate a combustion gas; and a downstream zone connected downstream of the combustion zone and configured to exhaust the combustion gas toward the rear opening, an upstream zone configured to generate a flow of compressed air obtained by compressing an air taken in through the front opening; a combustion zone connected downstream of the upstream zone and configured to combust a mixture in which fuel is injected into the flow of compressed air, to generate a combustion gas; and a downstream zone connected downstream of the combustion zone and configured to exhaust the combustion gas toward the rear opening, wherein a cavity is provided on the first surface in the combustion zone, wherein the first passage forming member comprises: at least one convex section located in the upstream zone and provided on the first surface to protrude toward the second surface from the first surface; a first fuel injection section configured to inject fuel to the flow of compressed air; and a second fuel injection section configured to inject fuel to the cavity, and at least one convex section located in the upstream zone and provided on the first surface to protrude toward the second surface from the first surface; a first fuel injection section configured to inject fuel to the flow of compressed air; and a second fuel injection section configured to inject fuel to the cavity, and wherein the second passage forming member comprises a third fuel injection section configured to inject fuel to a direction toward the first surface from the second surface in the passage, characterized in that the first fuel injection section is configured to inject the fuel to the flow of compressed air through a first fuel nozzle provided for the convex section, and the third fuel injection section is configured to inject the fuel to a direction toward the first surface from the second surface in the passage through a second fuel nozzle provided on the second surface in the downstream zone such that the injected fuel restrains or stops the flow of the combustion gas.