A toy gun with a built-in hand-tool assembly includes a gun housing and a hand-tool assembly; the gun housing has a concave slot and an inner wall formed inside the concave slot; the inner wall has a stopping portion formed thereon; the hand-tool assembly is detachably attached onto the concave slot; the hand-tool assembly includes a tool housing and a hand-tool; the hand-tool is received in the tool housing and has one end exposed out of the tool hosing; the tool hosing is configured to be fitted onto the concave slot; the hand-tool is configured to be blocked and positioned by the stopping portion. Therefore, with such structure, the toy gun includes the hand-tool built therein in order to facilitate the detachment, assembly or piercing of the air bottle in the toy gun by the user such that the convenience of use of the toy gun is increased.