The invention discloses a head circumference measuring device, which comprises a clip and a strip in structure. The clip fastener includes a body, a channel, a holding plate and a scale. The body has a holding groove, and the channel penetrates the body and is communicated with the holding groove. The buckle is arranged in the holding groove, and one side of the buckle has a hook part, which can move up and down in the channel. One end of the belt piece is provided with a tooth part, and the other end is coupled with the clip fastener, wherein the tooth part end of the belt piece can pass through the channel provided with the clip fastener. The scale is arranged at the tooth end of the belt member.在此揭示一種頭圍測量器，在結構上包括一卡扣件和帶狀件。所述卡扣件包括一本體、通道、扣持片和一刻度。本體具有一容置槽，通道貫穿所述本體且與容置槽連通。扣持片設於容置槽內，且扣持片之一側具有一勾部，其可於通道內上下移動。帶狀件一端具有一齒部，另一端與該卡扣件耦接，其中帶狀件的齒部端可穿設卡扣件的通道。所述刻度設於帶狀件的齒部端。
