Top heater, method for manufacturing semiconductor device, substrate processing method, and substrate processing apparatus

Deformation of a heating element is suppressed. A top heater provided above a reaction tube is provided with: a disc-shaped base material; and heating elements continuously overspread on the base material across a plurality of regions divided in a fan shape by a circle centered on the center of the base material, each of the heating elements overspread in the plurality of regions being connected to the heating element in the adjacent region at a predetermined point, the base material having a groove corresponding to the shape of the heating element, the wall is formed by a portion other than the portion where the groove is provided, and the interval between the heating elements laid in each of the two adjacent regions is configured to be wider than the width of the wall separating the two regions. 抑制发热体的变形。一种设于反应管的上方的顶部加热器，其具备：圆板状的基材；以及发热体，其跨将以基材的中央为中心的圆以扇形状分割成的多个区域连续地铺满于基材上，在多个区域内铺满的各个的发热体与相邻的区域的发热体在预定的一部位连接，基材具有与发热体的形状对应的槽，由设有槽的部位以外的部位形成壁，在彼此相邻的两个区域内分别铺满的发热体的间隔构成为比将该两个区域间隔开的壁的宽度宽。