A method of estimating the congestion degree and the number of people with high accuracy and at a low cost, without requiring a surveillance camera, is provided. Provided are a congestion degree estimating step of estimating a congestion degree based on sensor information (such as acceleration information) of a portable terminal device, an average congestion degree calculating step of calculating an average congestion degree for each mesh (reference range) set in advance, based on the congestion degree estimated in the congestion degree estimating step for a plurality of portable terminal devices, and an estimated number-of-people calculating step of calculating an estimated number of people for each mesh by multiplying the average congestion degree calculated in the average congestion degree calculating step by a base number of people (maximum number of accommodated people) determined in advance for each mesh.