A micro smoke detector, comprising a base and a cover body axially moving along the base, wherein the cover body is provided therein with a detection part for detecting smoke concentration, a sound production part for generating sound waves, and a control circuit board for controlling the detection part and the sound production part; a side wall of the cover body is provided with a smoke inlet hole for smoke to enter the detection part; an elastic part configured to drive the cover body away from the base by means of an elastic effect is disposed between the cover body and the base; a limiting part that limits, by means of an abutting effect, the cover body from breaking away from the base is disposed between the cover body and the base; a surface, facing towards the base, of the control circuit board is provided with a first button triggered by movement of the cover body to the base; the first button is configured to control test and stop of the smoke detector; and the detection part and the sound production part are electrically connected to a power supply in the base, the base comprises a mounting plate and a tubular part connected to the mounting plate; a bottom of the tubular part is provided with a partition board; the partition board is recessed along an axial direction of the tubular part to form a battery cavity for accommodating a battery; and a top of the tubular part is provided with an opening for movement of the cover body, the micro smoke detector being characterized by a switch button configured to control switch-on and switch-off of the power supply is disposed between the base and the tubular part, the partition board is recessed towards the opening along an axial direction to form a groove; the groove extends along a circumferential direction of a tubular object to form a limiting plate; a retaining groove is formed between a bottom surface of the limiting plate and a bottom surface of the groove; a limiting block configured to slide into the retaining groove is disposed on the mounting plate; a side wall of the groove is provided with a first positioning block, and a side wall of the limiting block is provided with a first positioning groove that is matched with the first positioning block to limit rotation of the partition board, the switch button comprises a lifting column and a button base that is disposed on one side, facing towards the opening, of the partition board, wherein a channel for sliding of the lifting column is disposed and a second button that is disposed on the control circuit board; the lifting column is configured to trigger, by means of relative movement between the mounting plate and the tubular part, the second button to perform an action; an elastic member configured to drive the lifting column away from the second button by means of an elastic effect is disposed between a top of the lifting column and the second button; a through hole is disposed, in a through manner, in the channel towards an interior of the groove, and a bottom of the lifting column is provided with a startup block that runs through the through hole; and the startup block is provided with a guide bevel configured to drive, by means of contact with the limiting block during rotation, the lifting column to contact the second button. the micro smoke detector being characterized by a switch button configured to control switch-on and switch-off of the power supply is disposed between the base and the tubular part, the partition board is recessed towards the opening along an axial direction to form a groove; the groove extends along a circumferential direction of a tubular object to form a limiting plate; a retaining groove is formed between a bottom surface of the limiting plate and a bottom surface of the groove; a limiting block configured to slide into the retaining groove is disposed on the mounting plate; a side wall of the groove is provided with a first positioning block, and a side wall of the limiting block is provided with a first positioning groove that is matched with the first positioning block to limit rotation of the partition board, the switch button comprises a lifting column and a button base that is disposed on one side, facing towards the opening, of the partition board, wherein a channel for sliding of the lifting column is disposed and a second button that is disposed on the control circuit board; the lifting column is configured to trigger, by means of relative movement between the mounting plate and the tubular part, the second button to perform an action; an elastic member configured to drive the lifting column away from the second button by means of an elastic effect is disposed between a top of the lifting column and the second button; a through hole is disposed, in a through manner, in the channel towards an interior of the groove, and a bottom of the lifting column is provided with a startup block that runs through the through hole; and the startup block is provided with a guide bevel configured to drive, by means of contact with the limiting block during rotation, the lifting column to contact the second button.