A construction machine, comprising: a first member having a first connecting portion adjacent to a retract space formed in the construction machine, the first connecting portion being formed of a first pin hole (131L, 131R) opened toward the retract space and penetrating the first connecting portion in a first penetration direction, a second member having a second connecting portion disposed at a position opposite to the retract space across the first connecting portion, the second connecting portion being formed of a second pin hole (133L, 133R) penetrating the second connecting portion in a second penetration direction at a position aligned with the first pin hole (131L, 131R) in the first penetration direction, a connecting pin supported by the first member or the second member so as to be movable within a range between a connecting position and a non-connecting position, the connecting position being a position in which the connecting pin is inserted into the first pin hole (131L, 131R) and the second pin hole (133L, 133R) to connect the first member and the second member to each other, and the non-connecting position being a position to which the connecting pin moves in a retract direction in which the connecting pin is retracted from the connecting position to the retract space along the first through direction and the second penetration direction to release the connection between the first member and the second member, and a movement prevention mechanism capable of preventing the connecting pin disposed at the connecting position from moving to the non-connecting position in the retract direction, characterized in that the connecting pin has an abutted surface disposed so as to face the retracting direction, the movement prevention mechanism includes an abutting member having an abutting portion capable of abutting the abutted surface of the connecting pin and is supported by the first member or the second member on the distal end side of the retract direction relative to the second connecting portion so that the abutting portion can move between an abutting position and a non-abutting position, the abutting position being a position in which the abutting portion is disposed so as to face the abutted surface on the tip side in the retracting direction relative to the abutted surface, and the abutting portion abuts on the abutted surface to prevent the connecting pin from moving from the connecting position to the non-connecting position in the retracting direction, and the non-abutting position is a position in which the abutting portion moves in a direction intersecting the retract direction so as to be separated from the abutted surface and allows the connecting pin to move from the connecting position to the non-connecting position. a first member having a first connecting portion adjacent to a retract space formed in the construction machine, the first connecting portion being formed of a first pin hole (131L, 131R) opened toward the retract space and penetrating the first connecting portion in a first penetration direction, a second member having a second connecting portion disposed at a position opposite to the retract space across the first connecting portion, the second connecting portion being formed of a second pin hole (133L, 133R) penetrating the second connecting portion in a second penetration direction at a position aligned with the first pin hole (131L, 131R) in the first penetration direction, a connecting pin supported by the first member or the second member so as to be movable within a range between a connecting position and a non-connecting position, the connecting position being a position in which the connecting pin is inserted into the first pin hole (131L, 131R) and the second pin hole (133L, 133R) to connect the first member and the second member to each other, and the non-connecting position being a position to which the connecting pin moves in a retract direction in which the connecting pin is retracted from the connecting position to the retract space along the first through direction and the second penetration direction to release the connection between the first member and the second member, and a movement prevention mechanism capable of preventing the connecting pin disposed at the connecting position from moving to the non-connecting position in the retract direction, characterized in that the connecting pin has an abutted surface disposed so as to face the retracting direction, the movement prevention mechanism includes an abutting member having an abutting portion capable of abutting the abutted surface of the connecting pin and is supported by the first member or the second member on the distal end side of the retract direction relative to the second connecting portion so that the abutting portion can move between an abutting position and a non-abutting position, the abutting position being a position in which the abutting portion is disposed so as to face the abutted surface on the tip side in the retracting direction relative to the abutted surface, and the abutting portion abuts on the abutted surface to prevent the connecting pin from moving from the connecting position to the non-connecting position in the retracting direction, and the non-abutting position is a position in which the abutting portion moves in a direction intersecting the retract direction so as to be separated from the abutted surface and allows the connecting pin to move from the connecting position to the non-connecting position.