An apparatus for butt joining two sheet members (50a, 50b) comprising: a supporting plate; a movable arm spaced from the supporting plate by a predetermined distance and being capable of moving toward or away from the supporting plate; and a pair of opposed joint units (4a, 4b) arranged at the supporting plate and the movable arm, respectively, each of the pair of joint units (4a, 4b) being provided with two gear wheels (21a, 21b, 21c and 21d) and two drawing rolls (11a-d) aligned in a direction in which the movable arm extends, each gear wheel (21a-d) having a circular truncated cone shape and at least one groove extending in a circumferential direction on the outer circumferential surface of the gear wheel (21a-d), each pair of the two gear wheels (21 a, 21b, 21c and 21d) on each joint unit (4a, 4b) being capable of rotating synchronously, each drawing roll (11a-d) having a cylindrical shape, each pair of the two drawing rolls (11a-d) on each joint unit (4a, 4b) being capable of rotating synchronously, the supporting plate and the movable arm being moved toward one side in a longitudinal direction of the movable arm with respective edges of the two sheet members (50a, 50b) to be joined being sandwiched between the pair of joint units (4a, 4b) to bring the edges closer together and butt join edge faces (51a, 51b) of the sheet members (50a, 50b), wherein the drawing rolls (11a-d) of the movable arm are arranged ahead in an advancing direction of the supporting plate and the movable arm, and the gear wheels (21a-d) of the movable arm are arranged behind in the advancing direction, characterized in that: each drawing roll (11a-d) has at least one groove extending in a circumferential direction on the outer circumferential surface of the drawing roll (11a-d); and the drawing rolls (11a-d) of the supporting plate are arranged ahead in an advancing direction of the supporting plate and the movable arm, and the gear wheels (21a-d) of the supporting plate are arranged behind in the advancing direction. a supporting plate; a movable arm spaced from the supporting plate by a predetermined distance and being capable of moving toward or away from the supporting plate; and a pair of opposed joint units (4a, 4b) arranged at the supporting plate and the movable arm, respectively, each of the pair of joint units (4a, 4b) being provided with two gear wheels (21a, 21b, 21c and 21d) and two drawing rolls (11a-d) aligned in a direction in which the movable arm extends, each gear wheel (21a-d) having a circular truncated cone shape and at least one groove extending in a circumferential direction on the outer circumferential surface of the gear wheel (21a-d), each pair of the two gear wheels (21 a, 21b, 21c and 21d) on each joint unit (4a, 4b) being capable of rotating synchronously, each drawing roll (11a-d) having a cylindrical shape, each pair of the two drawing rolls (11a-d) on each joint unit (4a, 4b) being capable of rotating synchronously, the supporting plate and the movable arm being moved toward one side in a longitudinal direction of the movable arm with respective edges of the two sheet members (50a, 50b) to be joined being sandwiched between the pair of joint units (4a, 4b) to bring the edges closer together and butt join edge faces (51a, 51b) of the sheet members (50a, 50b), wherein the drawing rolls (11a-d) of the movable arm are arranged ahead in an advancing direction of the supporting plate and the movable arm, and the gear wheels (21a-d) of the movable arm are arranged behind in the advancing direction, characterized in that: each drawing roll (11a-d) has at least one groove extending in a circumferential direction on the outer circumferential surface of the drawing roll (11a-d); and the drawing rolls (11a-d) of the supporting plate are arranged ahead in an advancing direction of the supporting plate and the movable arm, and the gear wheels (21a-d) of the supporting plate are arranged behind in the advancing direction. each drawing roll (11a-d) has at least one groove extending in a circumferential direction on the outer circumferential surface of the drawing roll (11a-d); and the drawing rolls (11a-d) of the supporting plate are arranged ahead in an advancing direction of the supporting plate and the movable arm, and the gear wheels (21a-d) of the supporting plate are arranged behind in the advancing direction.