The purpose of this study is to estimate the number of pedestrians and to show the change of pedestrian flow, using the pedestrian survey data of Toyohashi City in 1960~2010. To explain the pedestrian flow, we formulate a grid street model in which the flow is separated into the flow from (or to) Toyohashi station(S-Flow) and the flow in the grid edges (G-Flow). By the least square method, we estimate the numbers of S-Flow and G-Flow and show the change of flow of Toyohashi in 1960~2010. The estimated results are, for example, that the number of S-Flow is 7,400persons and the number of S-Flow is 2300persons in 2010, and the total number of pedestrians is decreasing in 1960~2010.