A folding cup holder is provided with a base plate; a pair of first arms having proximal end portions, being pivotally supported to the base plate; a pair of second arms each including a resilient latch portion, being pivotally supported to the base plate at proximal end portions thereof respectively; and a holder arm including a pair of engagement portions at both ends thereof and pivotally supported to the distal ends of the first arms and the distal ends of the second arms in differential axes. The engagement portions are engaged with the latch portions so that the holder arm is kept in an expanded state. The latch portions are resilient so that the engagement portions are allowed to override the resilient latch portions, thereby the holder arm is released to be free when excessive force is applied to the holder arm.