An organic layer deposition apparatus includes a transfer unit; a first conveyer unit including a guide member having accommodation grooves, a first accommodation part, a second accommodation part, and a connection part that connects the first accommodation part to the second accommodation part; a second conveyer unit for moving the transfer unit without the substrate; a loading unit for fixing the substrate on the transfer unit; a deposition unit including a chamber and an organic layer deposition assembly; and an unloading unit for separating the substrate, wherein the first accommodation part of the guide member is located close to ground compared to the second accommodation part, and includes a lower member, an upper member, elastic members located between the lower and upper members. The substrate fixed on the transfer unit is spaced from the organic layer deposition assembly while being transferred by the first conveyer unit.