An optical fiber splicing unit , comprising: a mechanical splice which aligns optical fibers and puts the optical fibers between half-split elements to splice the optical fibers to each other; a splice holder portion which holds the mechanical splice ; fixing member guide portions which respectively guide anchoring fixation members that are respectively fixed to the optical fibers at two sides of the held mechanical splice ; anchoring portions which respectively anchor the anchoring fixation members , the anchoring fixation members being respectively guided by the fixing member guide portions and adapted for advancing the anchoring fixation members ; and a first spacer which is configured to restrict the advancement of a first anchoring fixation member by abutting the first anchoring fixation member and is disposed to be configured to retract from a position in which the first spacer abuts the first anchoring fixation member , the anchoring fixation member being adapted for being guided by one fixing member guide portion and the fixing member guide portion also allowing advancing wherein a first optical fiber is fixed to the first anchoring fixation member , when gripping and fixing a tip of the first optical fiber to the mechanical splice in a state where a first anchoring fixation member abuts a first spacer which restricts advancement of the first anchoring fixation member , the first anchoring fixation member is configured to advance toward the mechanical splice by retracting the first spacer , and a bend is configured to be formed in the first optical fiber between the mechanical splice and the first anchoring fixation member by the advancement of the first anchoring fixation member . a mechanical splice which aligns optical fibers and puts the optical fibers between half-split elements to splice the optical fibers to each other; a splice holder portion which holds the mechanical splice ; fixing member guide portions which respectively guide anchoring fixation members that are respectively fixed to the optical fibers at two sides of the held mechanical splice ; anchoring portions which respectively anchor the anchoring fixation members , the anchoring fixation members being respectively guided by the fixing member guide portions and adapted for advancing the anchoring fixation members ; and a first spacer which is configured to restrict the advancement of a first anchoring fixation member by abutting the first anchoring fixation member and is disposed to be configured to retract from a position in which the first spacer abuts the first anchoring fixation member , the anchoring fixation member being adapted for being guided by one fixing member guide portion and the fixing member guide portion also allowing advancing wherein a first optical fiber is fixed to the first anchoring fixation member , when gripping and fixing a tip of the first optical fiber to the mechanical splice in a state where a first anchoring fixation member abuts a first spacer which restricts advancement of the first anchoring fixation member , the first anchoring fixation member is configured to advance toward the mechanical splice by retracting the first spacer , and a bend is configured to be formed in the first optical fiber between the mechanical splice and the first anchoring fixation member by the advancement of the first anchoring fixation member . <EOS>