A vehicle step apparatus (1; 1a; 1b; 1c; 1d) that projects from a railway vehicle in which it is installed so as to bridge a gap between the railway vehicle and a platform, comprising: a pair of step links that are provided as a pair of link members, and are supported so as to be able to swing around respective supporting points; a step block that is a block-shaped member for supporting the pair of step links at the supporting points via a rotation shaft (1.9a, 19b); a step base that is fixed to a main body of the railway vehicle and includes a first guide portion for limiting swing of the pair of step links so that ends of the step links on one side are movable only along a direction that is parallel to an opening width direction of a door opening of the railway vehicle, and a second guide portion for limiting movement of the step block so that the step block is movable only along a direction that is orthogonal to the opening width direction and is horizontal; a pair of step plates that are provided as a pair of plate-shaped members by which other ends of the pair of step links are respectively supported via rotation shafts (26a, 26b), and are installed so as to be movable between an accommodation position of being accommodated in the railway vehicle and a projection position of having projected from the railway vehicle; a sliding board (15; 33) that is arranged at a position of being offset with respect to the pair of step plates in an up-and-down direction when the pair of step plates are located at the accommodation position, and that slides with respect to the pair of step plates when the pair of step plates project toward the projection position while separating from each other in the direction parallel to the opening width direction; and a first actuator (16; 31; 32; 36) that drives the pair of step plates so as to project outward from the railway vehicle in a vehicle width direction of the railway vehicle. a pair of step links that are provided as a pair of link members, and are supported so as to be able to swing around respective supporting points; a step block that is a block-shaped member for supporting the pair of step links at the supporting points via a rotation shaft (1.9a, 19b); a step base that is fixed to a main body of the railway vehicle and includes a first guide portion for limiting swing of the pair of step links so that ends of the step links on one side are movable only along a direction that is parallel to an opening width direction of a door opening of the railway vehicle, and a second guide portion for limiting movement of the step block so that the step block is movable only along a direction that is orthogonal to the opening width direction and is horizontal; a pair of step plates that are provided as a pair of plate-shaped members by which other ends of the pair of step links are respectively supported via rotation shafts (26a, 26b), and are installed so as to be movable between an accommodation position of being accommodated in the railway vehicle and a projection position of having projected from the railway vehicle; a sliding board (15; 33) that is arranged at a position of being offset with respect to the pair of step plates in an up-and-down direction when the pair of step plates are located at the accommodation position, and that slides with respect to the pair of step plates when the pair of step plates project toward the projection position while separating from each other in the direction parallel to the opening width direction; and a first actuator (16; 31; 32; 36) that drives the pair of step plates so as to project outward from the railway vehicle in a vehicle width direction of the railway vehicle.