An accessory strap securing mechanism is positioned in a portable electronic device to assemble an accessory strap thereon. The portable electronic device defines an assembling slot. The accessory strap securing mechanism includes an assembling portion and a securing member. The assembling portion is formed in the portable electronic device. The securing member includes a fixing portion and a holding portion. The fixing portion is fixed to the assembling portion. The holding portion includes a clasp, and the clasp is deformed to allow the accessory strap to separate when a force applied to the accessory strap exceeds a predetermined amount.