1. An internal combustion engine control device comprising: a learning map having a plurality of grid points and storing a learning value of a control parameter used for control of an internal combustion engine at each of the grid points, capable of being updated; weight setting unit for setting a weight of each grid point of the learning map when the control parameter is acquired and for decreasing the weight of the grid point as a distance from a reference position which is a position of the acquired value of the control parameter on the learning map to the grid point becomes larger; and weighting learning unit for executing weighting learning control for updating the learning value of the respective grid points so that, each time the control parameter is acquired, the larger the weight is, the more the acquired value of the control parameter is reflected in the learning value at all the grid points.