A diesel engine comprising: a cam shaft that is driven by a crankshaft; a fuel injection pump driving cam that is provided on the cam shaft; a fuel injection pump driving cam that is provided on the cam shaft; and an intake cam that is provided on the cam shaft and configured to drive an intake valve; wherein the fuel injection pump driving cam has a minimum radius portion, a first slant portion, a maximum radius portion, a second slant portion, an intermediate portion, a third slant portion, an upper portion, a fourth slant portion, and the minimum radius portion in order of the forward rotation direction wherein the portions have different radii, the minimum radius portion is a part having a minimum radius among the fuel injection pump driving cam, the maximum radius portion is a part having a maximum radius among the fuel injection pump driving cam, the intermediate portion is a part having a radius smaller that of the maximum radius portion and larger than that of the minimum radius portion, the first slant portion is a part where a radius is changed from that of the minimum radius portion to the maximum radius portion along the forward rotation direction, the second slant portion is a part where a radius is changed from that of the maximum radius portion to the intermediate portion along the forward rotation direction, the third slant portion is a part where a radius is changed from that of the intermediate portion to the upper portion along the forward rotation direction, the fourth slant portion is a part where a radius is changed from that of the upper portion to the minimum radius portion along the forward rotation direction, the upper portion is a part having a radius smaller that of the maximum radius portion and larger than that of the intermediate portion, in a stage where a roller of the fuel injection pump abuts against the upper portion, the intake valve is a substantially full-open state, at a time of reverse rotation of the fuel injection pump driving cam, in a stage where the roller abuts against the fourth slant portion continued from the upper portion, the intake valve is an open state and the fuel is injected. a cam shaft that is driven by a crankshaft; a fuel injection pump driving cam that is provided on the cam shaft; a fuel injection pump driving cam that is provided on the cam shaft; and an intake cam that is provided on the cam shaft and configured to drive an intake valve; wherein the fuel injection pump driving cam has a minimum radius portion, a first slant portion, a maximum radius portion, a second slant portion, an intermediate portion, a third slant portion, an upper portion, a fourth slant portion, and the minimum radius portion in order of the forward rotation direction wherein the portions have different radii, the minimum radius portion is a part having a minimum radius among the fuel injection pump driving cam, the maximum radius portion is a part having a maximum radius among the fuel injection pump driving cam, the intermediate portion is a part having a radius smaller that of the maximum radius portion and larger than that of the minimum radius portion, the first slant portion is a part where a radius is changed from that of the minimum radius portion to the maximum radius portion along the forward rotation direction, the second slant portion is a part where a radius is changed from that of the maximum radius portion to the intermediate portion along the forward rotation direction, the third slant portion is a part where a radius is changed from that of the intermediate portion to the upper portion along the forward rotation direction, the fourth slant portion is a part where a radius is changed from that of the upper portion to the minimum radius portion along the forward rotation direction, the upper portion is a part having a radius smaller that of the maximum radius portion and larger than that of the intermediate portion, in a stage where a roller of the fuel injection pump abuts against the upper portion, the intake valve is a substantially full-open state, at a time of reverse rotation of the fuel injection pump driving cam, in a stage where the roller abuts against the fourth slant portion continued from the upper portion, the intake valve is an open state and the fuel is injected.