A power supply device of a tape-end detecting sensor for a tape recorder. The power supply device comprises a reel cover disposed on a sub-chassis, with a tape-end detecting sensor being seated on the reel cover for detecting the passing of a terminal end of a magnetic portion of a magnetic tape, a first power transmitting member mounted in the reel cover to be connected to the detecting sensor and having a first contacting portion, and a second power transmitting member disposed on the sub-chassis and having a second contacting portion that comes into contact with the first contacting portion when the reel cover is mounted on the sub-chassis. The power supply device further comprises a resilient pressing member integrally formed with the sub-chassis, for resiliently pressing the second contacting portion toward the first contacting portion to improve a contacting force between the first and the second contacting portions.