A substrate storage container includes a body including a bottom surface and a plurality of sidewalls extending perpendicularly from the bottom surface in a first direction to cooperatively provide an accommodating space for receiving a substrate, a first engaging portion provided in at least one sidewall of the plurality of sidewalls of the body and including a plurality of first positioning latching members which is arranged toward the accommodating space in a second direction perpendicular to the first direction, and a first positioning block detachably engaged with the first engaging portion and including a second positioning latching member which is engaged with any one of the plurality of first positioning latching members to adjust a capacity of the accommodating space corresponding to an engagement position of the second positioning latching member in the second direction.