A machining time estimation apparatus 20, capable of accurate machining time calculation, including a database 22 for storing the actual operation time data of miscellaneous functions, an actual operation time calculation section 21 for calculating the actual operation time of each miscellaneous function to update the data stored in the database 22, and an operation time estimation section 24 for analyzing an NC program, block by block, for calculating the estimated operation time of axis movement on the basis of the result of the analysis, for estimating the operation time of each miscellaneous function by searching the database 22 and for calculating the estimated operation time of each block and the estimated machining time of the whole program on the basis of the estimated operation time of the axis movement and the estimated operation time of the miscellaneous function.