The invention discloses an equivalent-time rainfall rain sample meter, belongs to the fields of hydrology and meteorology and particularly relates to a device for measuring the rainfall according to period of time. The equivalent-time rainfall rain sample meter comprises a primary rain receiving hopper, a casing, a takeover tube, a secondary rain hopper, a water-dividing catheter, a stepped motor control device and a rainfall measuring cup, wherein the primary rain receiving hopper is inserted into the casing and is connected with the takeover tube; the secondary rain receiving hopper is arranged below the takeover tube; the lower part of the secondary rain receiving hopper is connected with the water-dividing catheter; two ends of the water-dividing catheter are closed; a downward-opening hole is arranged at the far end of the water-dividing catheter; and the rainfall measuring cup is arranged below the downward-opening hole. The invention has the advantages that: firstly, the equivalent-time division of rain can be realized by a stepping motor for the first time; and secondly, the time division is quite fine by replacing the rainfall measuring cups and shortening the each-step stay time of the stepping motor as long as the number of the rainfall measuring cups is enough.