A battery powered fishing line bite detector alarm producing visible and/or audible alarm signals is disclosed. An arm, installed within the alarm, integrally connects to a modified leaf on-off switch. The alarm attaches to a fishing rod in front of a fishing reel mounted on the rod. Fishing line is threaded into the arm and adjusted such that slack is provided between the rear of the alarm and the front of the reel thereby allowing forward arm movement. The fishing line is further inserted until desired resistance of forward and backward line movement within the arm is achieved. Applied tension to the line forces the arm to actuate. A tension spring clip connected to a switch lever, and a common leaf contact arm, pulls contact arm closer to an upper common contact point until contact is made activating the alarm signals. Increased tensioning pulls the line through a variable sized slit and into a line hole, releasing tension on the arm and causing the contact arm and contact point to break contact, while allowing the arm to return to a self-adjusting alarm casing position.