Abstract: A door closer has a fixing set, a bidirectional set and an extending set. The fixing set has an elongated tube. The elongated tube has two opposite sidewalls and an opening. The bidirectional set is connected to the fixing set, is movably mounted in the elongated tube and has a connecting panel formed on and protruding from the bidirectional set and extending out of the opening. The extending set is pivotally connected to the bidirectional set and has a guiding track, an extending arm, a locking board and a connecting panel. The extending arm is movably mounted in the guiding track and has a connecting end extending out of the guiding track. The locking board engages the guiding track and is connected to the extending arm to adjust a total length of the extending set. The connecting panel is connected to the connecting end of the extending arm.

Abstract: A door closer has a fixing set, a bidirectional set and an extending set. The fixing set has an elongated tube. The elongated tube has two opposite sidewalls and an opening. The bidirectional set is connected to the fixing set, is movably mounted in the elongated tube and has a connecting panel formed on and protruding from the bidirectional set and extending out of the opening. The extending set is pivotally connected to the bidirectional set and has a guiding track, an extending arm, a locking board and a connecting panel. The extending arm is movably mounted in the guiding track and has a connecting end extending out of the guiding track. The locking board engages the guiding track and is connected to the extending arm to adjust a total length of the extending set. The connecting panel is connected to the connecting end of the extending arm.