A start controller for an engine, wherein the engine includes: plural cylinders (2; 2A to 2F); fuel supply means configured to supply fuel to each of the cylinders (2; 2A to 2F); a piston that is provided in each of the cylinders (2; 2A to 2F) in a reciprocal manner; a crankshaft configured to rotate in an interlocking manner with reciprocating motion of the piston; and an intake passage through which intake air to be introduced into each of the cylinders (2; 2A to 2F) flows, and wherein start means is capable of forcibly starting the engine by causing the crankshaft to rotate, the start controller comprising: position detection means (SN1, SN2) configured to detect a position of the piston in each of the cylinders (2; 2A to 2F); intake pressure detection means configured to detect an intake pressure in the intake passage; and control means configured to control the fuel supply means, and the start means, wherein the control means is configured to stop a fuel supply into the cylinder (2; 2A to 2F) by the fuel supply means to stop the engine when a specified engine stop condition is satisfied, start the engine by the start means when a specified engine start condition is satisfied after a stop of the engine, determine whether the position of the piston in each of the cylinders (2; 2A to 2F) detected by the position detection means (SN1, SN2) is within a specified target range after the stop of the engine, and start the engine by the start means when the engine start condition is not satisfied, in the case where the position of the piston in each of the cylinders (2; 2A to 2F) is out of the target range and the intake pressure is lower than an atmospheric pressure, characterized in that the control means is configured to start the engine by the start means when the engine start condition is not satisfied, in the case where the position of the piston in each of the cylinders (2; 2A to 2F) is out of the target range, and the intake pressure detected by the intake pressure detection means is lower than the atmospheric pressure and equal to or higher than a specified determination pressure that is lower than the atmospheric pressure. position detection means (SN1, SN2) configured to detect a position of the piston in each of the cylinders (2; 2A to 2F); intake pressure detection means configured to detect an intake pressure in the intake passage; and control means configured to control the fuel supply means, and the start means, wherein the control means is configured to stop a fuel supply into the cylinder (2; 2A to 2F) by the fuel supply means to stop the engine when a specified engine stop condition is satisfied, start the engine by the start means when a specified engine start condition is satisfied after a stop of the engine, determine whether the position of the piston in each of the cylinders (2; 2A to 2F) detected by the position detection means (SN1, SN2) is within a specified target range after the stop of the engine, and start the engine by the start means when the engine start condition is not satisfied, in the case where the position of the piston in each of the cylinders (2; 2A to 2F) is out of the target range and the intake pressure is lower than an atmospheric pressure, characterized in that the control means is configured to start the engine by the start means when the engine start condition is not satisfied, in the case where the position of the piston in each of the cylinders (2; 2A to 2F) is out of the target range, and the intake pressure detected by the intake pressure detection means is lower than the atmospheric pressure and equal to or higher than a specified determination pressure that is lower than the atmospheric pressure.