A sound source control information generating apparatus, comprising: a first acquisition means obtaining a first output value (Prs2) which is an output value of a sensor (43,44) capable of detecting striking on each of a plurality of struck heads; a second acquisition means obtaining a second output value (Prs1) which is an output value of a sensor capable of detecting a state that an object is placed on each of the struck heads; and an information generating means, wherein if the first output value (Prs2) with respect to one struck head is obtained through the first acquisition means, the one struck head serves as a target struck head, and the information generating means generates information for controlling a sound source means such that a sound generation process performed by the sound source means differs according to whether the first output value (Prs2) obtained with respect to the target struck head or a value (x) corresponding to the first output value (Prs2) is greater than a predetermined threshold value (SN, RN), wherein the information generating means: uses a value different from a reference value as the predetermined threshold value (SN, RN) if the second output value (Prs1), equal to or greater than a predetermined value, obtained through the second acquisition means is obtained at least over a first period before a timing that the first output value (Prs2) is obtained through the first acquisition means, and uses the reference value as the predetermined threshold value (SN, RN) if the second output value (Prs1), equal to or greater than the predetermined value, obtained through the second acquisition means is not obtained at least over the first period before the timing. a first acquisition means obtaining a first output value (Prs2) which is an output value of a sensor (43,44) capable of detecting striking on each of a plurality of struck heads; a second acquisition means obtaining a second output value (Prs1) which is an output value of a sensor capable of detecting a state that an object is placed on each of the struck heads; and an information generating means, wherein if the first output value (Prs2) with respect to one struck head is obtained through the first acquisition means, the one struck head serves as a target struck head, and the information generating means generates information for controlling a sound source means such that a sound generation process performed by the sound source means differs according to whether the first output value (Prs2) obtained with respect to the target struck head or a value (x) corresponding to the first output value (Prs2) is greater than a predetermined threshold value (SN, RN), wherein the information generating means: uses a value different from a reference value as the predetermined threshold value (SN, RN) if the second output value (Prs1), equal to or greater than a predetermined value, obtained through the second acquisition means is obtained at least over a first period before a timing that the first output value (Prs2) is obtained through the first acquisition means, and uses the reference value as the predetermined threshold value (SN, RN) if the second output value (Prs1), equal to or greater than the predetermined value, obtained through the second acquisition means is not obtained at least over the first period before the timing. uses a value different from a reference value as the predetermined threshold value (SN, RN) if the second output value (Prs1), equal to or greater than a predetermined value, obtained through the second acquisition means is obtained at least over a first period before a timing that the first output value (Prs2) is obtained through the first acquisition means, and uses the reference value as the predetermined threshold value (SN, RN) if the second output value (Prs1), equal to or greater than the predetermined value, obtained through the second acquisition means is not obtained at least over the first period before the timing.