A side-mount type engine control apparatus comprising: a housing; an axis unit provided rotatably in the housing; a control lever which is mounted on the axis unit, and is rotated to a forward side or a reverse side from a neutral position; a drive gear which rotates together with the axis unit; a driven gear which meshes with the drive gear; a sensor mounting plate arranged between a first side wall and a second side wall of the housing; and an angle sensor arranged on the sensor mounting plate; wherein the housing comprises a first housing element including the first side wall and a second housing element including the second side wall, the first housing element and the second housing element are connected to each other by a screw member, a plurality of fixing portions are formed in an internal space of the housing, the fixing portions are formed at positions where they do not interfere with a movable member in the internal space of the housing, the fixing portions extend in a thickness direction of the housing between the first side wall and the second side wall, in each of the fixing portions, a through-hole is formed, each of the through-holes is communicated with the first side wall and the second side wall in the thickness direction of the housing, a screw member for fixing the housing to a port-side mounting surface or a starboard-side mounting surface is inserted into the through-holes; a first fitting portion formed on a boss portion on a lower end side of the control lever; a second fitting portion provided on a side opposite to the first fitting portion of the boss portion; a first lever mounting portion including a first recess formed on one end portion of the axis unit; a second lever mounting portion including a second recess formed on the other end portion of the axis unit; a friction mechanism which applies friction to the axis unit and includes brake members (140, 141) in contact with a peripheral surface of the axis unit, and an adjustment portion which adjusts frictional force of the brake members (140, 141) and includes an adjustment screw which adjusts a pressure force of the brake members (140, 141) on the peripheral surface of the axis unit, and an operation portion which rotates the adjustment screw; a joint member including a coupling portion fitted to one of the first fitting portion and the second fitting portion, and a rotation prevention coupling portion fitted into one of the first recess and the second recess; and a center bolt which fixes the boss portion and the joint member to the axis unit. a housing; an axis unit provided rotatably in the housing; a control lever which is mounted on the axis unit, and is rotated to a forward side or a reverse side from a neutral position; a drive gear which rotates together with the axis unit; a driven gear which meshes with the drive gear; a sensor mounting plate arranged between a first side wall and a second side wall of the housing; and an angle sensor arranged on the sensor mounting plate; wherein the housing comprises a first housing element including the first side wall and a second housing element including the second side wall, the first housing element and the second housing element are connected to each other by a screw member, a plurality of fixing portions are formed in an internal space of the housing, the fixing portions are formed at positions where they do not interfere with a movable member in the internal space of the housing, the fixing portions extend in a thickness direction of the housing between the first side wall and the second side wall, in each of the fixing portions, a through-hole is formed, each of the through-holes is communicated with the first side wall and the second side wall in the thickness direction of the housing, a screw member for fixing the housing to a port-side mounting surface or a starboard-side mounting surface is inserted into the through-holes; a first fitting portion formed on a boss portion on a lower end side of the control lever; a second fitting portion provided on a side opposite to the first fitting portion of the boss portion; a first lever mounting portion including a first recess formed on one end portion of the axis unit; a second lever mounting portion including a second recess formed on the other end portion of the axis unit; a friction mechanism which applies friction to the axis unit and includes brake members (140, 141) in contact with a peripheral surface of the axis unit, and an adjustment portion which adjusts frictional force of the brake members (140, 141) and includes an adjustment screw which adjusts a pressure force of the brake members (140, 141) on the peripheral surface of the axis unit, and an operation portion which rotates the adjustment screw; a joint member including a coupling portion fitted to one of the first fitting portion and the second fitting portion, and a rotation prevention coupling portion fitted into one of the first recess and the second recess; and a center bolt which fixes the boss portion and the joint member to the axis unit.