To provide a flexible type study desk switchable between one-person use and two-person use by stretching and contracting a top plate.

The expandable study desk 1 includes a slide guide 5 fixed to the lower surface of a main top plate 2 and a slide frame 4 supported by the slide guide 5. The slide frame 4 is supported by the slide guide 5 so as to be slid in right and left directions. The expandable study desk 1 is converted to the study desk that has the top plate long in the right and left direction for two-person use by arranging the main top plate 2 and a sub top plate 3 in the right and left directions for two-person use, and is converted to the study desk to be used by one person, whose top plate includes only the main top plate 2 by detaching the sub top plate 3 from the top of the slide frame 4 for one-person use.